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Competition Litigation - UK Practice and Procedure, 2nd Edition edited by Brealey QC, Mark; George, Kyla (11th July 2019)

13 Expert Evidence

Mark Brealey, Kyla George

From: Competition Litigation: UK Practice and Procedure (2nd Edition)

Edited By: Mark Brealey QC, Kyla George

From: Oxford Competition Law (http://oxcat.ouplaw.com). (c) Oxford University Press, 2015. All Rights Reserved. Subscriber: null; date: 18 November 2019

Arbitration procedures — Appeals — Evidence — Judicial remedies

(p. 379) 13  Expert Evidence

Scope of chapter

This chapter considers the role of economic experts and economic analysis in competition-related litigation. Section A provides information on the duties and responsibilities of experts. Section B is a practical guide to the use of experts in the course of competition litigation, covering the requirements of the relevant CPR and CAT Rules.

A.  The Role and Responsibilities of Experts


13.01  Competition law involves the application of economic concepts and policy objectives in a legal framework. For example, a merger control law such as the Enterprise Act 2002 essentially defines a merger as objectionable if it results in a ‘substantial lessening of competition’ (or SLC), but this in itself does not describe in detail how such an outcome might arise, or how it should be measured.1 Similarly, Article 102 TFEU prohibits conduct by dominant firms that constitutes an abuse of that dominant position. While Article 102 TFEU itself provides four illustrations of the kinds of conduct that could meet this test for abuse, it falls short of describing what constitutes a dominant position or when conduct, such as selective low prices, causes sufficient harm to rivals or consumers so as to constitute an abuse. Case law and enforcement guidelines published by the authorities can provide some of the necessary (p. 380) information to convert these bare legal provisions into operational rules, but they still leave gaps.

Effects-based analysis

13.02  It is now well established that effects-based economic analysis has a significant role to play in the interpretation and application of the legal rules relating to competition. However, one of the most commonly cited issues with the use of economic experts in litigation is how best to make use of what can sometimes be complex theoretical concepts and/or empirical techniques in a way that can be intelligible to the court or the Competition Appeal Tribunal (CAT). The problem is understandable since, in contrast to the in-house processing power accessible to administrative competition authorities such as the Competition and Markets Authority (CMA), courts and the CAT do not have the same means available to enable them to conduct their own detailed assessments. Parties to a competition law dispute should ensure that the economic arguments are clearly stated and that they make a positive contribution to the argument and the outcome of the case, especially given the centrality of economic principles and empirical analysis to the substantive tests that lie at the heart of most competition law questions.

Difference between factual and expert evidence

13.03  Factual witnesses provide factual evidence, whereas expert witnesses provide opinion evidence.2 In many, if not most, competition cases it will be necessary to adduce expert evidence relating to matters such as market definition (both product and geographical), market power (particularly in Article 102 TFEU or Chapter II cases),3 and/or, in the case of a (p. 381) damages claim, quantum of the claimed loss,4 including in some cases, matters of causation.5

Issues addressed by expert evidence

13.04  In every case, care must be taken in appropriately formulating the issues to which any expert evidence is to be addressed, in order to avoid the experts expressing opinions on matters that are not properly the subject of expert evidence.6 In competition cases, the distinction between matters that are properly for the experts and those that are strictly issues of fact or law (and hence are not matters for the experts) can be a difficult one to draw.7 In Bookmakers Afternoon Greyhound Services v Amalgamated Racing Ltd,8 Morgan J did, however, emphasize the importance of properly applying this distinction.9 The Guidance for the Instruction of Experts similarly emphasizes that experts should keep questions of fact and opinion separate, clearly identifying those facts (whether assumed or otherwise) upon which their opinions are based, and, in cases where there are material facts in dispute, expressing separate opinions on each hypothesis put forward. The Guidance further provides that the expert should not express a view in favour of one or other disputed version of the facts unless, as a result of particular expertise and experience, they consider one set of facts as being improbable or less probable, in which event the expert may express that view and should give reasons for holding it.10

Expert evidence in the High Court

13.05  In the High Court, the rules that apply to the production of expert evidence are set out in CPR Part 35 as supplemented (p. 382) by Practice Direction 35 (PD 35) and the Chancery11 and Commercial Court Guides.12 In July 2012 the Civil Justice Council published its initial guidance for litigants, those instructing experts, and experts on best practice in complying with Part 35 of the CPR and court orders.13 The guidance has subsequently been amended and updated on a number of occasions, most recently in light of the Jackson reforms. The latest version of the guide, ‘Guidance for the Instruction of Experts in Civil Claims 2014’ (the ‘Guidance for the Instruction of Experts’),14 came into effect in August 2014, and replaced the previous Protocol for the Instruction of Experts to give Evidence in Civil Claims.15

Expert evidence in the CAT

13.06  The principles and procedures envisaged by CPR Part 35, PD 35, and the Guidance for the Instruction of Experts are also matters that are taken into account by the CAT. The CAT Rules and CAT Guide to Proceedings16 provide the Tribunal with further powers in relation to expert evidence and reflect many of the principles and procedures used in the High Court. Accordingly, there are many similarities between the approach that applies to the production of expert evidence in proceedings in the High Court and proceedings before the CAT, and many of the principles set out below are applicable to either type of proceedings.

General duties and responsibilities of experts

13.07  The duties and responsibilities of experts in relation to the court and parties are set out in CPR 35 and the Guidance for the Instruction of Experts.17 CPR rule 35.1 restricts expert evidence to that which is ‘reasonably required’ to resolve the proceedings. The introductory paragraph18 of the Guidance requires experts, and those instructing them, to have regard to the objectives underpinning the Pre-Action Protocols,19 that is, to:

  1. (a)  encourage the exchange of early and full information about the expert issues involved in the prospective claim;

  2. (b)  enable the parties to avoid or reduce the scope of the litigation by agreeing the whole or part of an expert issue before proceedings are started; and

  3. (c)  support the efficient management of proceedings where litigation cannot be avoided.

(p. 383) These key principles were considered in detail by Cresswell J in National Justice Compania Naviera SA v Prudential Assurance Co Ltd (The ‘Ikarian Reefer’),20 in a passage that has been frequently cited with approval. They include the following:

  1. (a)  expert evidence should be, and should be seen to be, the independent product of the expert uninfluenced in form or content by the exigencies of litigation;

  2. (b)  the expert witness should provide independent assistance to the court by way of objective unbiased opinion in relation to matters within his or her expertise;

  3. (c)  the expert should state the facts or assumption on which his or her opinion is based;

  4. (d)  the expert should make it clear when a particular question or issue falls outside his or her expertise;

  5. (e)  the expert should make it clear if he or she has been unable to reach a definitive opinion; and

  6. (f)  if, after exchange of reports, the expert witness changes his or her view on the material having read the other side’s expert report or for any reason, such change of view should be communicated to the other side without delay.

Relevant provisions in the CPR and CAT Guide

13.08  In the High Court these requirements are now reflected in paragraphs 2.1–2.6 of PD 3521 and paragraphs 11–14 of the Guidance for the Instruction of Experts,22 whereas in the CAT they are reflected in paragraphs 7.65–7.70 of the CAT Guide.

Experts to whom these provisions apply

13.09  CPR rule 35.2(1) defines an expert to which CPR rule 35 applies as a person who has been instructed to give or prepare expert evidence for the purpose of proceedings. Accordingly, the provisions of the CPR, the Guidance for the Instruction of Experts, and the CAT Rules or Guide do not apply to advice obtained from an expert before proceedings are started which the parties do not intend to rely upon in litigation. The same applies where, after the commencement of proceedings, experts are instructed only to advise a party and not to prepare evidence for use in the proceedings. In such a case the expert’s role is that of an expert adviser, not an expert to whom the CPR provisions or the provisions of the CAT Rules or Guide apply. However, if an expert who was formerly instructed only to advise is later instructed as an expert witness to prepare or give evidence for the proceedings, the CPR and Guidance for the Instruction of Experts or CAT Rules and Guide will then apply to them.23

Duty to assist the Court or the Tribunal

(p. 384) 13.10  Under CPR rule 35.3, an expert is subject to an express duty to help the court on the matters within his or her expertise. This duty overrides any obligation owed to the person from whom the expert has received instructions or by whom he or she is paid.24 The Guidance for the Instruction of Experts further explains that in this respect experts are under an obligation to assist the court to achieve the overriding objective of dealing with cases justly, which includes dealing with cases proportionately (keeping the work and costs in proportion to the value and importance of the case to the parties), expeditiously, and fairly.25 Paragraph 7.67 of the CAT Guide similarly provides that it is the duty of the expert to help the CAT on matters within his or her expertise, and that this duty overrides any obligation to any party.

Independence of an expert

13.11  An expert giving evidence to a court or the CAT is required to express his or her views independently of the parties. A useful test of independence is ‘that the expert would express the same opinion if given the same instructions by another party’.26 Paragraph 7.67 of the CAT Guide further emphasizes that an expert witness should never assume the role of an advocate and should not omit to consider material facts which could detract from the expert’s concluded opinion.


13.12  In their reports, experts must expressly state that they understand their duty to the court or the Tribunal and that they have complied with that duty.27 Given the importance of independence in this respect, experts are required to disclose any potential conflict of interest as soon as possible,28 and certainly ought to do so in their report.29 The issue whether a proposed expert who discloses such a conflict should be permitted to give evidence should then generally be determined in the course of case management in advance of the trial,30 although in some (p. 385) circumstances (for example where the real extent of the interest or connection is not sufficiently clear) the court or the CAT may not be able to resolve the question of independence at the interlocutory stage.31 ‘Where an expert has a material or significant conflict of interest, the court is likely to decline to act on his evidence or indeed to give permission for his evidence to be adduced.’32 An example of a conflict which is almost certainly likely to lead to such a result is the existence on the part of an expert of a direct financial interest in the outcome of the case.33

Not every connection to a party will lead to the expert’s evidence being disregarded

13.13  As a general rule, it is always desirable that an expert should have no actual or apparent interest in the outcome of the proceedings in which he or she gives evidence, but such disinterest is not automatically a precondition to the admissibility of his or her evidence.34 It has been held that a properly qualified expert who understands that their primary duty is to the court or CAT is not necessarily disqualified from giving evidence by the fact that he or she is employed by one of the parties, although in any given case it will depend on the employee’s status and the nature of the work carried out.35 The test of apparent bias is accordingly not relevant to the question of whether or not an expert should be permitted to give evidence. Instead, the questions which have to be determined are whether (a) the person has lowered expertise as a result of the connection and (b) the person is aware of their primary duty to the court or the CAT if they give expert evidence and is willing and able, despite the connection with the party, to carry out that duty. The fact of the connection may nonetheless affect the weight to be afforded to the evidence.36 These considerations were applied by Rimer J in Chester City (p. 386) Council v Arriva plc37 when rejecting the submission that the evidence of an expert who had acted as a consultant to one of the parties for some years prior to the litigation should be disregarded on the ground of lack of impartiality. In so ruling, the judge expressly recognized that the expert’s ‘undoubted closeness to the action would make him unsuitable to give expert evidence if the relevant test were that he should display the same absence of connection with the party calling him as, for example, must anyone engaged in a judicial function’, but concluded that this was ‘not the test when considering the ability of someone to give expert evidence’. Rimer J did, however, acknowledge that as the expert in question ‘had been very close to the action on the claimants’ side of the record’ there was ‘therefore a risk that his opinion may perhaps have become unconsciously coloured by the claimants’ interests’. This risk was therefore to be borne in mind in assessing the weight to be given to the expert evidence.

Internal experts

13.14  In certain competition cases involving a challenge to a regulatory decision, the regulator may wish to call one of its internal experts who was involved in the decision-making process to give evidence on matters which have been addressed by an independent expert for the opposing party. The CAT has accepted such an approach.38 The evidence given by such an individual may extend beyond purely factual information (for example as to the process that was adopted leading to the decision) and also encompass matters of opinion. In such a case, the conduct of any joint meeting between experts may be affected, as it may not be possible for them to be instructed freely to make concessions in relation to matters the subject of the challenged decision.39

Membership of the CAT

13.15  In 2 Travel Group plc (In liquidation) v Cardiff City Transport Services Limited,40 the CAT was required to consider the unusual situation of one party (2 Travel Group) wishing to call a member of the CAT’s panel of ordinary members to give evidence. The opposing party contended that the evidence constituted expert evidence and ought to be excluded on grounds of apparent bias. The CAT rejected this contention, principally because appropriate steps had been taken to ensure that the members of the Tribunal hearing the case did not know the individual in question, and because it concluded that the evidence in question was factual in nature and not expert evidence, such that 2 Travel Group did not have any choice about calling him. The CAT did, (p. 387) however, indicate that had 2 Travel Group sought to adduce true expert evidence from the individual after his appointment as an ordinary member of the CAT’s panel then either the individual would have refused to act or to continue to act, or, if he had not done so, the outcome of the application might have been different.41

Previous provision of privileged information to an expert by the opposing party

13.16  The principle that there is no property in a witness applies equally to expert witnesses.42 However, an expert who is in possession of privileged information of one party may be prevented from acting for the other party in circumstances where it is likely that the expert will be unable to avoid making use of the privileged information.43 In other cases where the expert can act without making use of the privileged information, the expert is able to act for the opposing party provided appropriate steps are taken (for example by the provision of an undertaking) to maintain the privilege.44

Matters within field of expertise

13.17  Experts should only provide opinions in relation to matters which lie within their expertise, and should indicate without delay where particular questions fall outside their expertise. Further, so far as matters within their expertise are concerned, they should confine their opinions to matters which are material to the dispute.45 In Sainsbury’s Supermarkets Ltd v MasterCard Incorporated and Others46 the CAT was less aided by the economic evidence than it might have been, on the basis that the experts were economists and not experts in the field of payment systems (the area on which they were asked to opine). As a result, the CAT considered that their expertise ‘was engaged at one remove: it could only be deployed in relation to substantial and complex factual material about which they were not expert’.47 The CAT, in providing guidance for the future, stated that in cases where significant economic evidence was (p. 388) being adduced by economic experts who lacked specific expertise in the particular factual field under consideration, the parties should be ‘especially assiduous’ in ensuring that the economic experts are: (a) clearly instructed on the legal principles they are to apply, and in particular any assumptions they are being required to make; and (b) absolutely clear as to the factual material on which their reports are to be based.48

Need to take account of all material facts

13.18  Experts should take into account all material facts before them, and identify the facts and materials upon which they have relied in forming their opinions. If necessary they should indicate if an opinion is provisional or qualified, where they consider that further information is required, or if for any reason they are not satisfied that an opinion can be expressed finally and without qualification.49

Continuing duty of correction

13.19  Experts should inform those instructing them without delay of any change in their opinions on any material matter and the reasons for this.50

Experts’ priority

13.20  Paragraph 83 of the Guidance for the Instruction of Experts indicates that experts instructed in cases have an obligation to attend court if called upon to do so and accordingly should take all reasonable steps to be available. In Imperial Tobacco Group plc v OFT, the CAT similarly indicated an expectation that the experts who had been instructed in the case should give the matter priority, and ensure that the process between the exchange of reports and the hearing, and at the hearing itself, should proceed smoothly.51

No immunity for experts

13.21  Historically, expert witnesses enjoyed immunity from liability in respect of their activities as an expert witness.52 However, in 2011, the Supreme Court held that this immunity should be abolished.53 The Guidance for the Instruction of Experts provides guidance on sanctions (under CPR 44) which may be imposed on the instructing party and/or experts for failure to comply with CPR 35, the PD, or court orders, that is, costs penalties against those instructing the expert or the expert him or herself, or the risk that the expert’s report or evidence becomes inadmissible.54 Expert witnesses do, however, retain an absolute privilege against claims in defamation.

(p. 389) B.  Experts: Procedural Requirements

1.  The instructions

Instructing an expert

13.22  The Guidance for the Instruction of Experts encourages those instructing experts to ensure they give clear instructions and attach relevant documents. Such information should include:55

  1. (a)  basic information, such as names, addresses, telephone numbers, dates of incidents and any relevant claim reference numbers;

  2. (b)  the nature of the expertise required;

  3. (c)  the purpose of the advice or report, a description of the matter(s) to be investigated, the issues to be addressed and the identity of all parties;

  4. (d)  the statement(s) of case (if any), those documents which form part of disclosure and witness statements that are relevant to the advice or report;

  5. (e)  where proceedings have not been started, whether they are contemplated and, if so, whether the expert is being asked only for advice;

  6. (f)  an outline programme, consistent with good case management and the expert’s availability, for the completion and delivery of each stage of the expert’s work; and

  7. (g)  where proceedings have been started, the dates of any hearings (including any case/costs management conferences and/or pre-trial reviews), the dates fixed by the court or agreed between the parties for the exchange of experts’ reports and any other relevant deadlines to be adhered to, the name of the court, the claim number, the track to which the claim has been allocated and whether there is a specific budget for the experts’ fees.

There is also a requirement that each party instructing experts should seek to agree, where practicable, the instructions for the experts with the other parties, and that each expert receives the same factual material.56 Other information, to be agreed in the terms of appointment, is the basis of the expert’s charges (e.g. daily or hourly rate and an estimate of the time likely to be required, or a fixed fee for the services), travelling expenses and disbursements, cancellation charges, and any fees for attending court.57 The terms should also state whether the expert’s charges will be subject to assessment if a party is publicly funded and include guidance that the expert’s fees and expenses may be limited by the court.58 The Guidance also strongly discourages the payment of experts’ fees being contingent upon the nature of the expert evidence or the outcome of the case.59

Experts to confirm acceptance of instructions promptly

(p. 390) 13.23  Experts are required to confirm ‘without delay’ whether they accept their instructions, and should inform those instructing them as soon as possible if the instructions are not acceptable (e.g. they are unclear, impose unrealistic deadlines, or require work that falls outside their expertise), are insufficient to complete the work, or give rise to a conflict for the expert;60 or if the expert is unable to comply with any of the terms of appointment, or orders that have been made.61

2.  Permission to adduce expert evidence

Admissibility in the High Court

13.24  Under CPR rule 35.4, it is necessary in the High Court to obtain the permission of the Court to call an expert or put an expert’s report in evidence,62 at which stage it will also be necessary to identify the field of the expert evidence and, where practicable, the name of the expert on whose evidence the party wishes to rely. CPR rule 35.4(2) also requires the parties at the same time to provide an estimate of the costs of the proposed expert evidence, and to identify the issues which the expert evidence will address.63 CPR rule 35.4 has also been amended to provide that the order granting permission to adduce expert evidence may specify the issues which the expert evidence should address.64 These provisions, along with the Guidance for the Instruction of Experts, are intended to encourage the focusing of expert evidence at an early stage.

Admissibility in the CAT

13.25  The CAT Rules include separate sections on evidence in relation to appeal proceedings, review proceedings under the Enterprise Act 2002, and damages claims under section 47A of the Competition Act 1998.65 For appeals and damages claims, unless the CAT otherwise directs, no witness of fact or expert shall be heard unless the relevant witness statement or expert report has been submitted in advance of the hearing and in accordance with any directions (p. 391) of the Tribunal.66 The Tribunal has a general power to give directions as to the evidence which may be required or admitted in proceedings and the extent to which it must be oral or written.67

In appeals and judicial review proceedings, expert evidence is (so far as is practicable) generally served together with the notice of appeal or application,68 defence,69 or statement of intervention.70 Nonetheless, in relation to appeals, CAT rule 21(d) provides that the Tribunal may give directions on whether the parties are permitted to provide expert evidence. Furthermore, in appeals, the parties are required to sign a statement identifying the expert evidence the substance of which was not referred to in the administrative phase.71 CAT rule 21(2) sets out a non-exhaustive list of criteria that the Tribunal will have regard to in deciding whether to admit or exclude evidence. These include:

  1. (a)  the statutory provision pursuant to which the appeal is brought and the applicable standard of review being applied by the Tribunal;

  2. (b)  whether or not the substance of the evidence was available to the respondent before the disputed decision was taken;

  3. (c)  where the substance of the evidence was not available to the respondent before the disputed decision was taken, the reason why the party seeking to adduce the evidence had not made it available to the respondent at that time;

  4. (d)  the prejudice that may be suffered by one or more parties if the evidence is admitted or excluded; and

  5. (e)  whether the evidence is necessary for the Tribunal to determine the case.

In relation to judicial review, in BAA v Competition Commission72 the CAT indicated that the introduction of detailed technical expert evidence in applications for review under section 179 of the Enterprise Act is strongly to be discouraged and will be disallowed other than in very clear cases.73 It further stated that (p. 392) where a party making an application under section 179 for review of a decision wishes to contend that expert evidence should be admitted on the application, the proper course (save in exceptional circumstances) will be either to annex to the application the expert evidence on which it wishes to rely, and include in the body of the application notice an application for the CAT to grant permission to the parties with a request that the application be determined at the earliest opportunity; or (if the party wishes to have a determination from the CAT before incurring the expense of producing an expert report) simply to include such an application in the body of the application notice. The CAT further emphasized the importance of such applications being made and determined at the earliest possible stage of the proceedings, and if at all possible before the respondent is put in a position where it must expend time and expense in responding to the expert evidence in question. The position has now been formally expressed in rule 27 of the 2015 CAT Rules, pursuant to which the applicant is required to serve with his application for review an application to adduce such expert evidence, attaching either the statement of expert evidence on which he wishes to rely or a detailed explanation of the nature of the expert evidence that he wishes to adduce.74

In damages claims, permission is required to adduce expert evidence. Pursuant to CAT rule 54(3)(g), permission is sought at the first case management conference (CMC), and it is at this stage that the relevant areas of expertise and the type of evidence will be discussed. In Socrates Training Ltd v The Law Society of England and Wales75 the CAT refused the defendant’s application to widen the ambit of expert evidence made at a previous CMC. The primary reason was that, as the proceedings had been allocated to the fast track procedure under CAT rule 58, the parties were required to proceed expeditiously. The application had been made extremely late and the limitation of expert evidence (to issues of market definition and dominance) had been made clear in the previous Order.

Limits on the extent of expert evidence

(p. 393) 13.26  Both the High Court and the CAT have a duty to restrict the extent of expert evidence adduced to that which is reasonably required in any case.76 The scope of this mandatory requirement was considered by Mr Justice Hildyard in The RBS Rights Issue Litigation,77 in which he noted that even where the parties are agreed, it was for the Court to determine whether to give permission for particular expert evidence. The test set out in CPR rule 35.1 contains two elements: (a) is the evidence admissible; and (b) is the evidence reasonably required (and not just potentially useful) to resolve the proceedings. So far as admissibility is concerned, the relevant question is whether there is a recognized body of expertise governed by recognized standards and rules of conduct relevant to the question which the Court has to decide. Unless there is, the Court should decline to admit evidence which ex hypothesi is not evidence of any body of expertise but rather the subjective opinion of the intended witness.78 In determining whether particular evidence is reasonably required, a key question will be whether the subject matter of the opinion is such that a person without instruction or experience in the area of knowledge or human experience would be able to form a sound judgment on the matter without the assistance of witnesses possessing special knowledge or experience in the area.79 The burden of establishing that expert evidence is both (a) admissible and (b) reasonably required is on the party which seeks permission to adduce the evidence concerned.80 Directions relating to such matters will usually be given at the first CMC,81 although they can also be made at a later stage.82

In Generics UK Limited v Competition and Markets Authority,83 Roth J summarized the CAT’s view in relation to an application to adduce a further rebuttal expert evidence’s report as follows:

First, the Tribunal should manage a case actively so that expert evidence can be handled effectively and efficiently at the hearing of the appeals. The challenge for courts (p. 394) presented by economic evidence in competition cases has been the subject of much discussion, and it is a challenge even for a Tribunal of which one member may be a distinguished economist. Secondly, it is of great benefit for the Tribunal, and indeed all parties, if the views of the economic experts are set out in writing in advance. See also under the governing principle, Rule 4(5)(e): active case management includes planning the structure of the main hearing in advance with a view to avoiding unnecessary oral evidence. Thirdly, it is necessary to avoid a potentially endless ping-pong of expert evidence where each expert puts in a further report responding to criticism in the last report of the opposing expert. It is self-evident that there is a certain tension between the second and third of those considerations.

In this instance, it was considered ‘appropriate’ and ‘helpful’ and ‘would not cause any prejudice’ if the additional rebuttal report was submitted. However, Roth J limited the extent of the report and required a short timeframe for its submission.84

Limits on the extent of recoverable expert costs

13.27  Pursuant to CPR rule 35.4(4), the High Court can also limit the amount of a party’s expert’s fees and expenses that can be recovered from any other party. Lord Justice Jackson’s Review of Civil Litigation Costs: Final Report recommended that judges should make greater use of this power in advance of experts’ costs being incurred.85 The amendment to CPR rule 35.4(2) requiring parties at the permission stage to furnish estimates of the costs of their proposed expert evidence (see paragraph 13.24) is intended to facilitate the exercise of this power. The Guidance for the Instruction of Experts also makes specific provision for this at paragraph 17.

Changing experts

13.28  In the High Court, permission is required to change the identity of an expert either where the expert is named in the original order granting permission to serve an expert report or after an initial expert report has been served. Such permission will only be granted where the party seeking to switch has a good reason for changing expert. The mere fact that the previously chosen expert has modified or even changed his or her views will not suffice. If permission to change expert is refused, it will remain open to the relevant party to put to the other side’s expert in cross-examination points raised by the new expert.86 In Clarke v Barclays Bank plc and another,87 permission to change expert was refused in circumstances where the claimant’s original expert had announced his retirement from the case after preparing his report, but the claimant had delayed very significantly before informing the other party of that fact. In consequence, the High Court concluded that the claimant’s conduct amounted to a serious abuse (p. 395) of the process of the court and the balance of justice came down firmly against granting permission to rely on the new expert.88

Earlier expert reports

13.29  It is clear that the High Court regards expert shopping as undesirable, and where possible will use its powers to prevent it. Thus, where a party has instructed an identified expert under CPR Part 35 and then seeks to change the identity of his expert, if the change is permitted the court will generally exercise its discretion to order disclosure of the original expert’s report.89 If the report is disclosed in response to such an order, it can generally be used by any party without calling the author of the report.90 In Edwards-Tubb v JD Wetherspoon plc,91 the Court of Appeal nonetheless acknowledged that the original report was privileged, and the client was therefore entitled to refuse to produce it. However, if they did so then they would not generally be permitted to adduce the report of another expert pursuant to CPR rule 35.4. The factor which appears particularly to have influenced the Court of Appeal in Edwards-Tubb92 to make an order preventing a party from adducing expert evidence is that the original expert had been instructed under CPR Part 35 before the commencement of proceedings. The rationale for this approach is that an expert who has prepared a report under CPR Part 35 is different from another witness, as his or her prime duty is unequivocally to the court. However, this principle is not necessarily confined to a case in which one party seeks to change experts during the course of proceedings. In Odedra v Ball93 Coulson J accepted that in light of the importance of openness under the CPR (which he concluded would, in certain instances, trump questions of privilege), there may be cases in which an expert who it was known had produced an earlier report relevant to the issues in dispute may have to disclose both reports as a condition of being permitted to give evidence at all.94

Waiver of privilege in draft report

13.30  Applying well-established principles, a party which deploys significant parts of a draft expert report in the context of an (p. 396) interlocutory application may be taken to have waived privilege in the draft notwithstanding an express claim to maintain privilege.95

Single joint expert

13.31  The parties can agree, and both the High Court and the CAT can require, that any expert evidence be provided by a single expert appointed jointly by all parties.96 There is detailed guidance on single joint experts, provision of joint instructions, and conduct of the single joint expert in the Guidance for the Instruction of Experts (paragraphs 33–46). Given the complexity of many competition cases, it may be that this power is unlikely to be much used in the competition field.97 However, there may be scope for its use in cases where the particular issue that is proposed as the subject of expert evidence falls within a substantially established area of knowledge, and where it is not necessary for the court or CAT to sample a range of opinion. An example might be a technical issue that is unlikely to be controversial between the parties. In the first CMC for Peugeot SA and others v NSK Ltd and others98 Green J rejected calls (before pleadings had closed) for the parties to instruct one joint expert on the basis that it was too early in the proceedings for a number of defendants, with a number of different interests, to identify all of the issues on which they would wish to instruct a joint single expert. The CAT’s Order granted permission to the parties to instruct their own single experts, with the provision for early engagement and an early meeting between the experts.99

The initial use of a single joint expert does not preclude a party from subsequently applying for permission to call expert evidence of its own if it is dissatisfied with the report produced by the single joint expert. However, the cost of such an expert will not be recoverable from another party.100 In Daniels v Walker101 the Court (p. 397) of Appeal indicated that in any substantial case where the instruction of a single expert is to be ordered, the correct approach is to regard the instruction of an expert jointly by the parties as the first step in obtaining expert evidence on an issue. However, if, having obtained the joint expert’s report, a party, for reasons that are not fanciful, wishes to obtain further expert evidence, it should (subject to the court’s discretion) be permitted to do so. The considerations relevant to the exercise of the court’s discretion in this respect were considered in further detail by Neuberger J (as he then was) in Cosgrove v Pattison.102

3.  Expert’s access to information

Expert materials103

13.32  In expressing views on matters such as market definition, an expert will usually need to conduct a detailed analysis of the factual conditions on the relevant markets. This often means drawing on different means of testing those conditions, including, for example, shock analysis, diversion ratio analysis, price correlation analysis, margin concentration analysis, and comparative analysis.104 In large competition cases, it is also often the case that a party’s chosen expert will need to draw on other materials, in relation to matters that relate to the subject matter of his or her report. Insofar as the materials upon which the expert is drawing are publicly available, no issue arises.105 An expert is clearly entitled to rely on such matters as part of the process of reaching his or her conclusion.106

Access to the same relevant information

13.33  The Guidance for the Instruction of Experts further provides that experts should try to ensure that they have access to all relevant information held by the parties, and that the same information has been disclosed to each expert in the same discipline (paragraph 30). If an expert realizes that the basis of his instructions is different from that of another expert, he should inform those who instruct him as soon as possible. Where the expert is relying on specific identified materials that are not publicly available, they should normally be served with the report at the latest.107 CPR rule 31.14(2) (p. 398) also confers power on the Court to order inspection of any document mentioned in an expert’s report which has not already been disclosed in the proceedings.108 Further, the Court has a discretion under CPR rule 35.9, which appears to have been rarely used to date, to direct a party who has access to information that is not reasonably available to the other party to prepare and file a document recording the information and to serve that document on the other party. The Guidance for the Instruction of Experts notes that attention should be drawn to the requirements of CPR rule 35.9: if such information is required by the expert but has not been disclosed, the expert should discuss the position with those instructing him so that a request can be made, setting out why the information is necessary and its significance in relation to the expert issues. If the information is not forthcoming, an application can be made to the court (paragraphs 31 and 32). The CAT would most likely deal with similar issues under its broad powers to give directions under rules 19 and 21 of the CAT Rules.

Additional factual evidence required for the purposes of expert evidence

13.34  In the High Court, evidence of a factual nature is usually required to be served in advance of the expert evidence,109 yet it may only become apparent as the expert actually settles down to write his or her report that particular factual evidence is required for that purpose. In such a case it will also be necessary to apply for permission to serve the relevant factual evidence out of time.

Reliance by an expert on work of others

13.35  If an expert relies on work undertaken by others and is not himself or herself sufficiently involved in the work to enable him or her to speak of it directly as part of his or her report,110 it will be necessary to consider whether to adduce evidence from the individual who actually conducted it, in addition to the evidence of the expert. Depending on the extent of the potential dispute in relation to the work in question, and its importance to the conclusions reached by the expert, it may be possible to avoid the need to call another witness by the use of a hearsay notice.111

Confidentiality rings

13.36  In competition cases where a confidentiality ring has been established, it is generally the case that the expert(s) instructed by the parties will be afforded the same level of access to confidential material as the external lawyers. (p. 399) In some cases, however, where the expert in question is an industry expert giving opinion evidence in relation to discrete issues, it may be appropriate to limit the scope of material provided to the expert in order to avoid the risk of further inadvertent disclosure of confidential material. Ultimately, the extent of the confidential material to be provided will be a matter for the court or CAT in each case.112

Requests for directions

13.37  The CPR, the Guidance for the Instruction of Experts, and the CAT Guide provide that an expert is entitled to ask for directions at any stage.113 An expert could, for example, make use of this provision in order to seek directions clarifying the material with which he or she has been provided for the purpose of producing his or her report.114 Before doing so in the High Court, an expert is required (unless the court orders otherwise) to provide a copy of any proposed request for directions first to the party instructing him or her, seven days before filing the request, and then to all other parties four days before filing. The purpose of this latter provision seems to have been to allow the parties to assist the expert in ensuring the clarity of his or her request, although there is obviously a concern that it could also allow the parties to seek to impose pressure on an expert (particularly a single joint expert) to desist from making any such request.115

4.  The written expert report

Exchange or sequential service

13.38  At the first CMC in the High Court, the court will also usually consider whether any expert evidence should be exchanged simultaneously or sequentially. Both the Chancery Guide and the Commercial Court Guide encourage the sequential exchange of reports in appropriate cases, on the ground that this may save time and costs by helping to focus the contents of the reports.116 Although the Report of the Commercial Court Long Trials Working Party (CCLTWP) went further and stated that the general rule should be that exchange of expert reports should be sequential, not simultaneous, this was not adopted in the Commercial Court Guide.117 The Commercial Court Guide does, however, indicate that sequential exchange is likely to be particularly effective (and presumably therefore is likely to be ordered) where experts are giving evidence of foreign law or are forensic accountants. It further states that this is an issue that the court will normally wish to consider at the CMC.118 The Guidance (p. 400) for the Instruction of Experts further explains the process where there is to be sequential exchange of experts’ reports.119

Role of the written report

13.39  The formal written report submitted by an economic expert clearly forms a key part of the economic evidence. Even if it is necessary for such a report to address complex questions of economic theory, or to present the results of technical empirical analysis such as econometric results or economic modelling, it is incumbent on the expert involved to do so in a manner that provides a clear account of what work has been done and why it is relevant to the underlying legal tests.

Formal and informal statements

13.40  Under CPR rule 35.5, an expert report is required to be given in a written report unless the court directs otherwise.120 There is no equivalent express provision in the CAT Rules or Guide, but it is equally generally the case that expert evidence is provided in a written report.121 On occasion, however, the CAT has also permitted informal statements of experts to be admitted.122

Formal requirements

13.41  In the High Court, the report must comply with the requirements set out in CPR rule 35.10 and PD 35. The report is required to contain statements to the effect that the expert understands his duty to the court and is aware of and has complied with the requirements of CPR Part 35, PD 35, and the Guidance for the Instruction of Experts.123 The report must also be verified by a statement of truth, the form of which can be found at PD 35, and paragraphs 3 and 52 of the Guidance. These requirements are essentially mirrored in paragraph 7.68 of the CAT Guide. Under CPR rule 35.13, a party who fails to serve an expert’s report in accordance with the court’s directions will not be entitled to use the report at trial or to call the expert to give evidence without the court’s permission.

Mandatory statement of the substance of all material instructions124

13.42  Of particular relevance is the requirement that the expert report should state the substance of all material instructions, whether written or oral, on the basis of which it is written.125 The objective of this requirement is that an expert’s instructions should be transparent. The precise application of this requirement can give rise to questions of some difficulty, and has yet to be fully explored by the courts or (p. 401) the CAT. All materials, including factual materials that are provided to an expert for the purpose of relying on them in a report, certainly constitute instructions for these purposes. However, the requirement is only to identify the ‘substance’ of those instructions that are ‘material’, with the result that a failure to refer to all such material does not necessarily amount to a failure to comply with this rule: Lucas v Barking Havering and Redbridge Hospitals NHS Trust.126 This requirement does, however, mean that considerable care has to be taken in supplying materials to an expert in circumstances where it may subsequently be the case that the party instructing that expert does not wish the expert to refer to that material in his or her report. An obvious example is provided by draft witness statements or notes of interviews with potential witnesses. If the evidence in question is clearly irrelevant to the issues on which the expert is required to opine, no problem arises. If, however, the evidence is relevant, the expert is put in a difficult position in circumstances where it is subsequently decided not to include a statement from the witness in question. Nevertheless, CPR rule 35.10(3) does not require disclosure of an early report prepared by an expert before he or she makes the report which is later disclosed in the litigation as being the evidence he or she intends to give at trial: Jackson v Marley Davenport.127

Disclosure of instructions

13.43  CPR rule 35.10(4) expressly provides that the instructions referred to in an expert report are not privileged against disclosure, but that the court will not, in relation to those instructions, order disclosure of any specific document or permit any questioning in court, other than by the party who instructed the expert, unless it is satisfied that there are reasonable grounds to consider the statement of instructions given to be inaccurate or incomplete. The purpose of CPR rule 35.10(4) is to prevent compliance with CPR rule 35.10(3) rendering such a statement disclosable unless the conditions set out in that rule are satisfied.128 In the ordinary way, therefore, the expert is to be trusted to comply with CPR rule 35.10(3): the effect of the CPR rule 35.10(4) restrictions is that the party on the other side may not as a matter of course call for disclosure of documents constituting the expert’s instructions as a check to see that CPR rule 35.10(3) has been fulfilled. Accordingly, there must be some concrete fact giving rise to ‘reasonable grounds’ within the closing words of CPR rule 35.10(4).129 There is no equivalent provision to CPR rule 35.10(4) in the CAT Rules or Guide, but given the similarity of the general approach applied in this area, it is to be expected that the CAT will seek to adopt a broadly equivalent approach.

Privilege attaching to draft reports

(p. 402) 13.44  As a general rule, drafts of the expert report or communications between the expert with the legal advisers to a party are privileged from production. However, that privilege can be waived if the contents of the draft or such communications are deployed in court.130

Amending an expert’s report

13.45  It may become necessary for an expert to amend his report. The Guidance for the Instruction of Experts states that experts ‘should not be asked to amend, expand or alter any parts of reports in a manner which distorts their true opinion, but may be invited to do so to ensure accuracy, clarity, internal consistency, completeness and relevance to the issues’.131 Experts should generally follow the recommendations of solicitors in relation to the form of reports, but must form their own independent views on the opinions and contents of the reports and not include any suggestions that do not accord with their views. The Guidance also suggests that if an expert alters an opinion following a meeting of experts, it will suffice to create a signed and dated note or addendum to that effect. If an expert changes his opinion significantly, following new evidence for example, he must inform those who instructed him and amend his report accordingly, explaining the reasons. The change of opinion should be notified to the other parties as soon as possible by those instructing the expert.132

Use by another party of a report that has been served

13.46  Under CPR rule 35.11, once a party has disclosed an expert’s report, any party may use that expert’s report as evidence at the trial. It is not necessary for a party wishing to do so to seek the court’s permission to adopt this course, although it should advise the other parties of its intention to do so, and for what purpose.133 Occasionally, and if the circumstances genuinely require it, the court may require a party wishing to rely on a report disclosed by his or her opponent to call the expert in question.134

Written questions to experts

13.47  Under CPR rule 35.6 a party may, without the court’s permission, put written questions about a report served by another party or a single joint expert to the expert. Any such questions have to be put on one occasion, within twenty-eight days of service of the report, and for the proper purpose of clarifying the report, unless the court otherwise orders or the parties otherwise agree. The answers provided by an expert in response to such a written (p. 403) request are to be treated as part of his or her report; they are covered by the statement of truth, and form part of the expert evidence. Experts have a duty to provide answers to questions properly put.135 If an expert does not provide an answer to such a written request, the court can order that the party who instructed that expert may not rely on his or her evidence, or may not recover the fees and expenses of that expert from the other party. The CAT Guide expressly envisages that a similar procedure could be used in appropriate cases before the CAT.136

Appropriateness of serving written questions

13.48  Whether it is appropriate to serve written questions under these provisions will depend on the precise circumstances of the case. On occasion it may well be sensible to do so, either for the purpose of elucidating at the earliest possible stage material that is necessary for a proper understanding of the opposing party’s expert’s report, or for the purpose of seeking to pin that expert down in writing prior to cross-examination. However, both the Chancery and Commercial Court Guides emphasize that the procedure of putting written questions is not intended to interfere with the procedure for an exchange of professional opinion in discussions between experts or to inhibit that exchange of a professional opinion. The Guides therefore go on to indicate that if questions are oppressive in number or content, or are not necessary for the proper purpose of clarification, the court ‘will not hesitate’ to disallow the questions and to make an appropriate order for costs against the party putting them.137 The Guidance for the Instruction of Experts provides that where experts believe that questions put are not properly directed to the clarification of the report, or have been asked out of time, they should discuss the questions with those instructing them and, if appropriate, with those asking the questions.138 An application to the court for directions should be the last resort and may be made by the expert themselves in the absence of agreement or application for directions by the party or parties.

5.  Discussions after service of reports

Discussions between experts and joint statements

13.49  In the High Court, it is usual for the court to direct under CPR rule 35.12 that the parties’ respective experts should have a discussion after service of their reports;139 not in an attempt to settle the case,140 but in order to produce a joint statement identifying areas of agreement and thereby narrow and identify those areas of disagreement.141 If such (p. 404) a meeting is to take place, the parties are generally required to discuss and if possible agree whether an agenda is necessary and if so attempt to agree one that helps the experts to focus on the issues which need to be discussed, and which is neither leading nor hostile in tone.142 Unless otherwise ordered, the parties or their legal representatives do not attend such meetings.143 Such meetings can also be ordered by the CAT in an appropriate case,144 and have been required in a number of cases.145 In the exercise of its case management powers, the CAT has also previously required a structured discussion between the parties and experts to be convened, in the presence of the CAT, in an endeavour to focus on the main points of dispute.146 Under the CAT Rules, the Tribunal now has the power to give directions as to the provision by parties of statements of agreed matters in relation to appeal proceedings and damages actions.147

At the end of discussions between the experts, a joint statement should be prepared which sets out:148

  1. (a)  issues that have been agreed and the basis of that agreement;

  2. (b)  issues that have not been agreed and the basis of the disagreement;

  3. (c)  any further issues that have arisen that were not included in the original agenda for discussion; and

  4. (d)  a record of further action, if any, to be taken or recommended, including if appropriate a further discussion between experts.

The joint statement should also include a brief restatement that the experts recognize their duties, as well as an express statement that they have not been instructed to avoid reaching agreement (or otherwise defer from doing so) on any matter within the experts’ competence. The joint statement should be agreed and signed by all the parties to the discussion as soon as possible.149

Multiple experts in a single discipline

(p. 405) 13.50  Competition cases often involve multiple parties, each of whom will seek to adduce the evidence of their own expert witness. It is accordingly common for there to be more than one expert in any given field expressing views on the same or overlapping issues. This can present particular issues of case management for the court or the CAT, which will not usually, for example, find it helpful to hear cross-examination of multiple experts on the same points. It can also give rise to issues as to the conduct of the joint meetings, as the party whose expert is in the minority may not welcome a meeting at which its expert is required to meet with the various experts from the other parties lined up against him or her. In Imperial Tobacco Group plc v OFT, the CAT resolved such a situation by accepting the suggestion of the OFT, the CMA’s predecessor, that there should be individual meetings between its expert and each of the experts instructed by the other parties, with each expert subsequently contributing to a single joint memorandum.150 In other cases before the Tribunal, the approach adopted has been to convene meetings attended by all the experts expressing views on a particular topic.151

The status of the experts’ discussions and the joint statement

13.51  Where conducted away from court or the CAT, the content of discussions between the experts is not to be referred to at trial, unless the parties agree.152 However, having attended such a joint meeting, the experts are usually required to prepare a statement setting out: (a) the issues on which they agree; and (b) the issues on which they disagree and a summary of their reasons for disagreeing.153 The status of the expressions of opinion provided in such a Joint Statement was considered by Morgan J in Bookmakers Afternoon Greyhound Services v Amalgamated Racing,154 when confronted with circumstances in which the claimant’s expert had in the joint statement expressed views on issues which he had not been instructed to consider, and had not considered, in his report. Nor had the claimant subsequently instructed him to produce a supplemental report addressing those issues. In such circumstances, Morgan J held155 that the permitted scope of the claimant’s expert’s evidence in chief was confined to his reports, and the record of his position on the other issues set out in the joint statement of experts did not form part of his evidence. In consequence, it was not necessary for the other parties to challenge the views set out only in the joint statement.

Non-binding nature of experts’ agreement

(p. 406) 13.52  Under CPR rule 35.12(5), and as reiterated in the Guidance for the Instruction of Experts,156 where experts reach agreement on an issue during their discussions, that agreement shall not bind the parties unless they expressly agree to be so bound. In practice, however, it is obviously going to be difficult to persuade a court or the CAT to disregard such an agreement. The Guidance further states that a party needs to be prepared to explain their refusal to be bound by the agreement, should it become relevant to the issue of costs.157

6.  Expert evidence at trial

Sequential evidence

13.53  The usual practice is for the court or the CAT to hear the oral evidence of the experts after the completion of the factual evidence, and, where there is more than one expert discipline or topic, by discipline or topic.158

Concurrent expert evidence or ‘hot tubbing’

13.54  Paragraphs 11.1–11.4 of PD 35 provide that at any stage in the proceedings the court may direct that some or all of the experts from like disciplines shall give their evidence concurrently, and set out the procedure that is then to apply. These provisions were inserted into PD 35 following Lord Justice Jackson’s Review of Civil Litigation Costs which considered the possibility of introducing this practice in the High Court, colloquially known as ‘hot-tubbing’.159

It is a practice which developed in Australia, following its initial use by the Australian Trade Practices Tribunal, now the Australian Competition Tribunal.160 The practice has some flexibility, so not all ‘hot tubs’ operate in precisely the same way.161 In the Australian model, the experts produce reports in the normal way and meet pre-trial in order to identify in a joint statement where they agree and where they disagree. Before the trial, the parties produce an agreed agenda for taking concurrent evidence based on the joint statement which contains a numbered list of the issues where the experts disagree. At trial, experts in the (p. 407) same discipline are sworn in at the same time and the judge chairs a discussion between the experts. The pre-trial document recording the matters upon which the experts disagree, serves as the agenda. Counsel join in the discussion and can put questions to the experts, as and when permitted by the judge. In addition, the experts can put questions to each other. Jackson LJ reported that in Australia this procedure had been found to be effective, to save both time and costs and to give back to experts their proper role of helping the court to resolve disputes. He recommended that the technique should be piloted in cases where the experts, the lawyers, and the judge consent.162 In 2010, a pilot scheme was commenced in the Manchester Technology and Construction Court and Mercantile Court, and subsequently extended to the Manchester Chancery Court, in which judges identified suitable cases and invited the parties to adopt the procedure at trial. Under the pilot guidelines, the procedure was not to be recommended where the credibility or independence of any of the experts was in doubt. The interim report was published in January 2012,163 following the use of the procedure in three cases.164 It stated: ‘As a procedure for enhancing the quality of judicial decision-making there seem to be significant benefits.’165

Paragraphs 11.1–11.4 of PD 35 (which were introduced with effect from 1 April 2013) broadly follow the Australian model described. They indicate that while the parties’ representatives may ask questions of the experts (once the discussion between the experts chaired by the judge has been conducted), such questioning may be designed to test the correctness of an expert’s view or seek clarification of it, and should not cover ground that has been fully explored already. A full cross-examination will therefore be neither necessary nor appropriate. The Guidance for the Instruction of Experts166 further encourages the use of this process: ‘Concurrent evidence can save time and costs, and assist the judge in assessing the difference of views between experts.’ It goes on to stipulate that experts need to be told in advance of the trial if the court has made an order for concurrent evidence.167

Hot-tubbing occurred in a competition context in the High Court in Streetmap v Google,168 where Mr Justice Roth expressed the view that the hot tub had led to a constructive exchange which considerably shortened the time taken by the (p. 408) economic evidence at trial, but had involved considerable preparation by the court and effectively required a transcript since the judge was unable to keep proper notes while leading the questioning.169 The hot-tubbing of experts occurred in the pay-for-delay appeals.170 A hybrid form of hot-tubbing occurred in Unwired Planet v Huawei171 (an abuse of dominance case relating to FRAND) where Mr Justice Birss held a ‘short period of concurrent evidence’ before the parties’ cross-examination in order to clarify the judge’s understanding of some of the economic issues.

Expert ‘teach-ins’

13.55  Prior to the experts giving evidence and being cross-examined, the experts may be required to provide the court or the CAT with a ‘teach-in’. In this way the experts go through in an uncontentious way, if possible, what they have done, what models they have used, and what methods they have applied.172


1  See, e.g., Enterprise Act 2002, s 22(1)(b).

2  The distinction between matters of fact and matters of opinion is not always easy to draw. For example, in many competition cases it will be necessary for the court or the CAT to have a detailed understanding of matters relating to the industry in question, often including matters of a technical nature. However, a witness who gives evidence (albeit based on his industry expertise) of the characteristics of a particular industry, or the likely costs of particular activities, is providing factual, not expert evidence: Albion Water Ltd v Water Services Regulation Authority [2007] CAT 1; [2007] Comp AR 505, para 135, applying Re Chemists Federation Agreement (No 2) [1958] 1 WLR 1192 and Richards & Wallington (Plant Hire) Ltd v Monk & Co [1984] Costs LR (Core Vol) 79. The content of this footnote was cited with approval by the CAT in British Telecommunications plc v Office of Communications [2010] CAT 17 at paras 109–110. See also 2 Travel Group plc (In Liquidation) v Cardiff City Transport Services Limited [2011] CAT 44; [2012] Comp AR 121, at paras 5–7. See also para H2.8 of the Commercial Court Guide, which provides that where an expert is relied on to establish primary facts as well as using his expertise to express an opinion related to, or in connection with the primary facts, that part of his evidence which is to be relied upon to establish the primary facts is to be treated as factual evidence, be incorporated into a factual witness statement, and be exchanged in accordance with the order for exchange of factual witness statements.

3  While it is common for such evidence to be provided by expert economists, in Chester City Council v Arriva plc [2007] EWHC 1373 (Ch) Mr Justice Rimer rejected the notion that ‘only trained economists with a list of learned articles to their name’ have the expertise necessary to understand the concepts to be investigated in a competition law case, stating that while those concepts ‘are no doubt most easily grasped, explained and opined upon by trained economists, they are concepts drawn from and related to the operation of the markets of the real world’: para 147.

4  For example, in 2 Travel Group plc (in liquidation) v Cardiff City Transport Services Limited [2012] CAT 19; [2012] Comp AR 211, the CAT heard expert evidence on the issue of what would have happened in the counterfactual scenario. In that case the CAT expressly rejected the suggestion that it was required to accept the evidence of one expert rather than the other on that issue, concluding: ‘It is for the Tribunal—based upon the factual evidence—to make an assessment of what would have happened in the counter-factual scenario, and this may very well involve re-working calculations done by the experts or adopting an approach which—although it draws on the work of both experts—adopts neither approach completely’: para 397.

5  For example, in 2 Travel Group plc, ibid, the claimant alleged that it had become insolvent as a result of the defendant’s predatory pricing. The defendant therefore wished to adduce expert forensic accountancy evidence in relation to the profitability of the claimant’s business. For an example of a case in which the CAT refused to permit expert evidence on quantum to be adduced on the ground that it was unnecessary and would disproportionately increase costs, see Albion Water v Dŵr Cymru Cyfyngedig [2012] CAT 23; [2012] Comp AR 437.

6  The inclusion in his or her expert report of matters of legal opinion can lead to criticism of the expert. See, e.g., Leeds City Council v Watkins [2003] UKCLR 467, at para 116.

7  For example, the correct application of the Art 101(3) TFEU criteria is a matter of law and not a matter for expert evidence. However, it may well be that there are issues relating to the correct application of those criteria that are properly the subject of expert evidence. Other issues that are not for the experts include the existence or otherwise of collusion, which is a matter of fact (Leeds City Council v Watkins, ibid, at para 107) and the existence of a potential adverse affect on trade which involves a matter of law (Leeds City Council v Watkins, ibid, para 106).

8  [2008] EWHC 1978 (Ch).

9  Ibid, paras 287–288 of the judgment.

10  See paras 57–58 of the Guidance for the Instruction of Experts.

11  Chancery Guide 2016 as amended.

12  Admiralty and Commercial Court Guide 2016 as amended.

14  This is annexed to PD 35.

15  Which had been previously annexed to PD 35.

16  The current CAT Rules (SI 2015/1648) and Guide to Proceedings came into force from 1 October 2015, and apply to any proceedings commenced before the Tribunal or on after 1 October 2015. Proceedings commenced prior to that date continue to be governed by the Competition Appeal Tribunal Rules 2003. Both are available at <www.catribunal.org.uk>. The 2015 CAT r 21 on Evidence is more comprehensive than its predecessor (r 22 in the 2003 CAT Rules). See also the 2015 CAT Guide to Proceedings on Evidence, at para 7.51 et seq, specifically para 7.65 in relation to expert evidence.

17  See paragraphs 9–16.

18  Guidance for the Instruction of Experts, para 2.

19  The Guidance also draws attention to the fact some cases will be governed by specific pre-action protocols and some may be ‘specialist proceedings’, as provided by CPR 49, where specific rules may apply (para 3).

20  [1993] 2 Lloyd’s Rep 68, para 81.

21  As well as the Chancery Guide, paras 4.8–4.9 and the Commercial Court Guide, Appendix 11.

22  Paragraph 7 of the Practice Direction (Pre-Action Conduct) further provides: ‘Parties should be aware that the court must give permission before expert evidence can be relied upon (see CPR r 35.4(1)) and that the court may limit the fees recoverable. Many disputes can be resolved without expert advice or evidence. If it is necessary to obtain expert evidence, particularly in low value claims, the parties should consider using a single expert, jointly instructed by the parties, with the costs shared equally.’

23  See also paras 6–8 of the Guidance for the Instruction of Experts.

24  The expert will also owe a duty to exercise reasonable skill and care to those instructing him and to comply with any relevant professional code. See para 9 of the Guidance for the Instruction of Experts.

25  Guidance for the Instruction of Experts, para 10.

26  See para 11 of the Guidance for the Instruction of Experts. The position of internal economists employed by a regulator who were involved in the process leading to the decision being challenged, and who accordingly would not appear to meet this test of independence, is addressed in para 13.14.

27  CPR r 35.10(2) and CAT Guide, para 7.68. In Aberdeen Journals v OFT [2003] CAT 11; [2003] Comp AR 67, the CAT indicated (para 288) that the absence of such a confirmation did not render the expert’s evidence inadmissible, but it did detract from the weight that the CAT felt able to place on it.

28  See para 22 of the Guidance for the Instruction of Experts. Experts should inform those instructing them (whether on initial instruction or at any later stage) ‘without delay’ if the instructions and/or work place them in any conflict with their duty as an expert. See, for example, R (Factortame Limited & ors) v Secretary of State for Transport, Local Government and the Regions (No 8) [2002] EWCA Civ 932; [2003] QB 381 at para 70.

29  See, e.g., Toth v Jarman [2006] EWCA Civ 1028, in which the Court of Appeal was required to consider the effect of a potential conflict of interest discovered after the conclusion of the trial.

30  R (Factortame Limited & ors) v Secretary of State for Transport, Local Government and the Regions (No 8) [2002] EWCA Civ 932; [2003] QB 381, at para 70. See also Helical Bar plc v Armchair Passenger Transport Ltd [2003] EWHC 367 (at para 29) and Gallaher International Ltd v Tlais Enterprises Ltd (No 2) [2007] EWHC 464 (Comm), at paras 82 and 83.

31  Meat Corporation of Namibia Ltd v Dawn Meats (UK) Ltd [2011] EWHC 474 (Ch), at para 46. In that case, Mann J held (at para 59) that the mere allegation that the proposed expert had been involved in some of the underlying facts (which the expert denied) ought not to be sufficient to disqualify the expert at the interlocutory stage. However, he went on to make clear that it was open to the opposing party to challenge the degree of the expert’s independence in cross-examination at trial.

32  Ibid, para 102.

33  See, e.g., the approach of the CAT in Albion Water Ltd v Water Services Regulation Authority [2007] CAT 1; [2007] Comp AR 505, para 138, in which the CAT expressed the view that an individual who was the principal shareholder in a company that owned the claimant was automatically disqualified from fulfilling the independence requirements of an expert as set out in the CAT Guide.

34  R (Factortame Limited & ors) v Secretary of State for Transport, Local Government and the Regions (No 8) [2002] EWCA Civ 932; [2003] QB 381, at para 70.

35  In Gallaher International Ltd v Tlais Enterprises Ltd (No 2) [2007] EWHC 464 (Comm) at paras 82 and 83, the party employing the expert took various steps to ‘ring-fence’ the expert during the course of the proceedings, and provided the expert with independent legal advice on his role. In Meat Corporation of Namibia Ltd v Dawn Meats (UK) Ltd [2011] EWHC 474 (Ch), Mann J rejected (at para 58) the suggestion that similar safeguards were necessary in any case where a party wished to tender its own employee as an expert.

36  Admiral Management Services Ltd v Para-Protect Europe Ltd, [2002] EWHC 233 (Ch). See also Field v Leeds City Council [1999] EWCA Civ 3013, Helical Bar plc v Armchair Passenger Transport Ltd [2003] EWHC 367 (at para 29), and Gallaher International Ltd v Tiais Enterprises Ltd (No 2) [2007] EWHC 464 (Comm).

37  [2007] UKCLR 1582.

38  Hutchinson 3G (UK) Limited v Ofcom (Mobile Call Termination) [2008] CAT 11, at para 175.

39  The CAT accepted that there may be such limitations, but considered that a joint meeting would nonetheless be useful in identifying the areas of disagreement in Virgin Media Inc and others v Ofcom, Case Nos 1156-1159/8/3/10, transcript of pre-hearing review, dated 23 March 2011, at pages 10–13.

40  [2011] CAT 44; [2012] Comp AR 121.

41  See para 13.

42  Harmony Shipping Co SA v Saudi Europe Line Ltd [1979] 1 WLR 1380, in which the Court of Appeal held that a handwriting expert who had accepted and performed instructions to comment on a document, and who subsequently also gave advice to the other side before declining to act for either party at trial, was susceptible to a summons to give evidence.

43  A Lloyd’s Syndicate v X [2011] EWHC 2487(Comm), per Teare J at para 32. See also Meat Corporation of Namibia Ltd v Dawn Meats (UK) Ltd [2011] EWHC 474 (Ch), at para 39, in which Mann J said that the court will intervene where the use of the privileged information was inevitable, citing R v Davies [2002] EWCA Crim 85 and Sage v Feiven [2002] CLY 430. In A Lloyd’s Syndicate, Teare J concluded that Mann J was not saying that inevitability was the test.

44  For example, in Meat Corporation of Namibia Ltd v Dawn Meats (UK) Ltd [2011] EWHC 474 (Ch), Mann J concluded (at paras 31–34) that an expert who had been provided with privileged information by one party could subsequently act for the other party, notwithstanding that the privileged information in question included some communications as to the merits of the litigation and approach to settlement, as that information could be adequately protected by the undertaking provided by the expert.

45  Paragraph 12 of the Guidance for the Instruction of Experts and para 7.67 of the CAT Guide.

46  [2016] CAT 11.

47  Ibid, para 37.

48  Ibid, para 41.

49  Para 13 of the Guidance for the Instruction of Experts and para 7.68 of the CAT Guide.

50  Para 14 of the Guidance for the Instruction of Experts.

51  Case Nos 1160-65/1/1/10. CMC transcript dated 8 April 2011, p 29.

52  Stanton v Callaghan [2000] QB 75.

53  Jones v Kaney [2011] UKSC 13.

54  See paras 86–89 of the Guidance for the Instruction of Experts. Para 89 provides that other possible sanctions include contempt of court (which may lead to fines or imprisonment), criminal sanctions in the event of perjury, or a claim against professional indemnity insurance for negligence.

55  See the Guidance for the Instruction of Experts, para 20.

56  Ibid, para 21.

57  Further guidance is provided at para 26, which states that experts should agree the terms on which they are to be paid with those instructing them: ‘Experts should be aware that they will be required to provide estimates for the court and that the court may limit the amount to be paid as part of any order for budgeted costs.’

58  Guidance for the Instruction of Experts, para 17.

59  Ibid, para 88. See also R (Factortame Limited & ors) v Secretary of State for Transport, Local Government and the Regions (No 8) [2002] EWCA Civ 932; [2003] QB 381 at para 73, in which the court said: ‘we consider that it will be a rare case indeed that the court will be prepared to consent to an expert being instructed under a contingency fee agreement.’

60  For more on this see para 13.11.

61  Guidance for the Instruction of Experts, para 23.

62  This rule has been interpreted as applying at the interlocutory, as well as trial, stage of proceedings. Accordingly, prior to serving an expert report for the purpose of supporting any application in the High Court, it is advisable, pursuant to CPR r 35.4, to seek permission to do so. In Sharp v Blank [2016] EWHC 776 (Ch) Nugee J refused (at para 37) to permit a party to claim the costs of adducing expert evidence in relation to an issue that arose on a summary judgment application for which permission had not been sought prior to the evidence being adduced.

63  Paragraph H2.1 of the Commercial Court Guide had already provided that the party applying for permission would normally be expected to identify to which issue or issues in the list of issues the proposed expert evidence relates, and to propose any amendments to the list of issues that might be required for this purpose. The Guidance for the Instruction of Experts also makes provision for this: see para 13.27.

64  These amendments form part of the amendments adopted in light of Lord Justice Jackson’s Costs Review Final Report.

65  CAT rr 21, 27, and 55 respectively.

66  CAT rr 21(3) and 55(2).

67  CAT r 19(2)(f).

68  CAT r 9(6) (appeal proceedings) and r 27 (applications for review). See also para 7.72 of the CAT Guide in relation to this requirement for the submission of new evidence in appeals and applications for review.

69  CAT r 15(5).

70  CAT r 16(9) (appeal proceedings). The CAT has a discretion to permit expert evidence to be served at a later date. In considering such an application, the CAT will give consideration to the CAT Rules and Guidance, fairness to the parties, and the need to consider the case proportionately: Rapture Television Plc v Office of Communications, British Sky Broadcasting Limited [2007] CAT 34 (at paras 123–126).

71  CAT r 9(4)(4)(h); CAT r 15(3)(f); CAT r 16(8)(d).

72  [2012] CAT 3; [2012] Comp AR 134, at paras 80–82.

73  BAA v Competition Commission [2012] CAT 3; [2012] Comp AR 134 was upheld in Lafarge Tarmac Holdings Limited v Competition and Markets Authority [2014] CAT 5; [2014] Comp AR 306, which was also an application for review under s 179 Enterprise Act 2002. The Tribunal rejected the application to submit fresh expert evidence on the basis that it is ‘not satisfied that there is a valid basis for departing from the generally restrictive approach to the admission of fresh evidence in judicial review proceedings, as laid down in the Powis case and endorsed in the BAA case’ (para 9). The Tribunal accepts that ‘exceptionally’ expert evidence may be admissible and useful to assist with technical issues, but in this case the Tribunal had sufficient expertise and experience to deal with the issues. Furthermore, it ‘would not be a welcome development’ if the doors were opened to applications for admission of expert evidence in issues of proportionality. The Tribunal was also mindful that allowing the fresh evidence would also increase costs, and usurp the function of the Tribunal (paras 10–11). The Tribunal has upheld the position taken in Lafarge in HCA International Limited v Competition and Markets Authority [2014] CAT 10, Ruling (Dismissing application to adduce expert evidence) and accompanying Reasoned Order [2014] CAT 9. Paragraph 7.78(a) of the CAT Guide summarizes the position as being that ‘The Tribunal is unlikely to admit new expert evidence in a judicial review case save in exceptional cases’.

74  In BAA v Competition Commission [2012] CAT 3; [2012] Comp AR 134, the CAT recognized (para 82) that these might include urgent merger cases in which there would not be time to have an application for permission to adduce expert evidence to be resolved, in which event the evidence in question would have to be lodged with the application. For an example of a case in which the CAT concluded it was too late for a party to seek to rely on new expert evidence that it had not adduced before the regulator, see BAA v Competition Commission (ibid), at para 75. See also para 7.75 of the CAT Guide.

75  [2016] CAT 19; [2017] Comp AR 45.

76  In the High Court, under CPR rr 35.1 and 35.4 and in the CAT Rules under rr 21(1) and 21(7), and 55(1) and 55(6). See also the CAT Guide, para 7.65, which specifically notes that expert evidence should be restricted to that which is reasonably required to resolve the proceedings. Para H2.1 of the Commercial Court Guide further provides that the court may limit the length of an expert report.

77  [2015] EWHC 3433(Ch). See also British Airways Plc v Spencer [2015] EWHC 2477, at 68.

78  Paras 13–14, citing the judgment of Evans-Lombe J in Barings Plc v Coopers & Lybrand [2001] PNLR 22.

79  Para 17, citing R v Bonython (1984) 38 SASR 45 and JP Morgan Chase v Springwell [2007] 1 All ER (Comm) 549.

80  Para 18.

81  Commercial Court Guide, para H2.1.

82  See, e.g., Chancery Guide, para 8.14, which states that the trial judge may disallow expert evidence which either is not relevant for any reason, or which he or she regards as excessive and disproportionate in all the circumstances, even though permission for the evidence has previously been given.

83  [2016] CAT 24; [2017] Comp AR 74, Ruling (Expert Evidence), para 5; see the summary of the final process in [2018] CAT 4 at para 73.

84  In Cityfibre v Office of Communications (BCMR) (Case No 1260/3/3/16) the parties were allowed to submit additional expert evidence without prejudice to any argument that material contained therein falls outside the scope of the appeals—Order dated 27 March 2017.

85  Chapter 38, para 3.18.

86  Guntrip v Cheney Coaches Ltd [2012] EWCA Civ 392, para 17.

87  [2014] EWHC 505 (Ch).

88  See para 27 of the Guidance for the Instruction of Experts, which deals with withdrawal of an expert.

89  Parties are expected to identify the names of their proposed experts at an early stage of the proceedings. Thus many of the pre-action protocols require the name of the expert to be identified. The standard Case Management Information Sheet in use in the Commercial Court and Chancery Division similarly requires the proposed expert to be named.

90  CPR r 35.11. In Edwards-Tubb v JD Wetherspoon plc [2011] EWCA Civ 136, the Court of Appeal indicated (at para 32) that in occasional cases where the circumstances really justified it, it might be appropriate to require the party wishing to rely on the report to call the expert to enable his or her evidence to be tested.

91  Ibid.

92  Ibid.

93  [2012] EWHC 1790 (TCC).

94  See, e.g., Axa Seguros SA de CV v Allianz Insurance plc and others [2011] EWHC 268 (Comm) in which the Commercial Court expressed the view that an expert might be required to disclose an earlier investigatory report if he was to give evidence.

95  ACD (Landscape Architects) Limited v Overall [2011] EWHC 3362 (TCC).

96  CPR r 35.7 and CAT Guide, para 7.66. Para 37 of the Guidance for the Instruction of Experts provides that in default of agreement on joint instructions to a single joint expert, each party may give instructions.

97  The CAT refused an application for a single joint expert on grounds of complexity and the size of the claim, notwithstanding the claimed inability of the claimant to instruct its own expert due to impecuniosity, in 2 Travel Group plc (In Liquidation) v Cardiff City Transport Services, Case No 1178/5/7/11, CMC on 18 April 2011. In other fields, the Court of Appeal has generally accepted that where issues are complex and the sums in dispute are large, it is not appropriate to require the use of a single joint expert. See, e.g., S (a Minor) v Birmingham Health Authority [2001] Lloyd’s Rep Med 382, and ES v Chesterfield and North Derbyshire Royal Hospital NHS Trust [2003] EWCA Civ 1284 (a £1.5m claim). See also the Commercial Court Guide, para H2.2.2, which expressly recognizes that where liability turns upon expert opinion evidence, it is usually appropriate for the parties to instruct their own experts.

98  Case No 1248/5/7/16.

99  Ibid: see Order dated 11 October 2016. A later Order, dated 29 November 2016, provided further detailed directions for the discussions to be held at the experts’ meeting, and a rigid timetable for progress thereafter. See further para 13.49.

100  See para 36 of the Guidance for the Instruction of Experts. CPR r 35.8(5) provides that unless the court otherwise directs, the relevant parties are jointly and severally liable for the payment of the single joint expert’s fees and expenses.

101  [2000] 1 WLR 1382.

102  [2001] CP Rep 68.

103  For a more detailed discussion on methodologies used by economists, see Chapter 16, Damages, at 16.08–16.14.

104  For an example of a case in which an expert was heavily criticized for failing properly to undertake such analyses, see Leeds City Council v Watkins [2003] UKCLR 467, paras 99–103.

105  For example, in addressing issues of market definition, market power, or theories of abuse, it is often possible to use established frameworks such as those provided by competition authority guidelines or notices in order to explain the context for the work that is done. Such guidelines are not perfect, but in general they have evolved towards a reasonably high degree of consensus on approaches to economic analysis that address the specific issues that are relevant to a competition law investigation.

106  See, e.g., R v Abadom [1983] 1 WLR 126 and H v Schering Chemicals [1983] 1 WLR 143. Such materials should obviously be provided to the other parties to enable their expert(s) to review them.

107  See para H2.20 of the Commercial Court Guide. In Imperial Tobacco Group plc v OFT, Case Nos 1160-65/1/1/10, the Tribunal indicated that in an appropriate case it might be appropriate to order disclosure of documents of a wider class than those relied upon by an expert to cover documents relevant to the findings made: transcript of CMC on 18 October 2010 at p 41.

108  See also para H2.21 of the Commercial Court Guide.

109  In appropriate cases, the Court or CAT can be requested to determine whether a person should be permitted to give evidence at an early stage of the proceedings.

110  An example in a competition case might be an econometric study conducted for the specific purposes of the proceedings by someone other than the expert, on the results of which the expert wished to rely in support of his or her conclusions. This is to be contrasted to the situation of an expert who is assisted by work performed by members of his or her team subject to the expert’s direction.

111  For further information on hearsay notices, see Chapter 12, Factual Evidence, at 12.24.

112  For a discussion on confidentiality rings, see Chapter 9, Disclosure, at 9.62.

113  CPR rule 35.14, Guidance for the Instruction of Experts, paras 28–29, and CAT Guide, para 7.69.

114  Leeds City Council v Watkins [2003] UKCLR 467, para 92.

115  Any request to the court for directions should be made by letter clearly marked ‘experts request for directions’ and contain information such as the claim number and title, the name of the expert, why directions are sought, and copies of any relevant documentation (para 29 of the Guidance for the Instruction of Experts).

116  Chancery Guide, para 4.15 and Commercial Court Guide, para H2.11.

117  CCLTWP Report, dated December 2007, paras 80 and 83(c).

118  Commercial Court Guide, para H2.11.

119  See para 61.

120  Model forms of experts’ reports are available from bodies such as the Academy of Experts and the Expert Witness Institute.

121  CAT Guide, para 7.68.

122  For example, see Claymore v OFT [2005] CAT 30; [2006] Comp AR 1 and the transcripts of the hearing in that case dated 14 January 2005.

123  See Guidance for the Instruction of Experts, para 51.

124  Ibid; for more detail see paras 47–59 of the Guidance.

125  CPR r 35.10(3), Guidance for the Instruction of Experts, para 54, and CAT Guide, para 7.68.

126  [2004] 1 WLR 220.

127  [2004] 1 WLR 2926.

128  Lucas v Barking Havering and Redbridge Hospitals NHS Trust [2004] 1 WLR 220, para 32.

129  Lucas v Barking Havering and Redbridge Hospitals NHS Trust [2004] 1 WLR 220, para 43, per Laws LJ.

130  ACD (Landscape Architects) Limited v Robert Overall, Cookham Construction Limited [2011] EWHC 3362 (TCC), in which one party set out extracts from a draft expert report in a witness statement served to support a strike-out application. In the costs hearing for this case ([2012] EWHC 100 (TCC)), the judge noted that the claimant no longer wanted to pursue its application in light of the defendants’ evidence and the draft expert report. For the principles applicable to waiver of privileged material in interlocutory hearings see Berezovsky v Abramovich [2011] EWHC 1143 (Comm).

131  Guidance for the Instruction of Experts, paras 62–63.

132  Ibid, para 64.

133  Gurney Consulting Engineers v Gleeds Health and Safety [2006] EWHC 43.

134  Edwards-Tubb v JD Wetherspoon plc [2011] EWCA Civ 136, at para 32.

135  Guidance for the Instruction of Experts, paras 65–67.

136  CAT Guide, para 7.66.

137  Chancery Guide, para 4.19 and Commercial Court Guide, para H2.19.

138  Guidance for the Instruction of Experts, para 67.

139  Parties may agree that experts’ discussions take place at any stage—Guidance for the Instruction of Experts, para 68.

140  PD 35, para 9.2.

141  Chancery Guide, para 4.16 and Commercial Court guide, paras H2.12 and H2.13. In Hubbard v Lambeth and Southwark and Lewisham Health Authority [2001] All ER (D) 11 (Sep), the Court of Appeal indicated that experience demonstrated that such a discussion was worthwhile in almost every case. Such discussions usually take place in a meeting, although under CPR r 35.12 there is no requirement that they do so. If a meeting is impractical, a telephone or video conference can therefore be arranged instead. See also the guidance provided at paras 68–81 of the Guidance for the Instruction of Experts.

142  PD 35, para 9.3. Para 4.17 of the Chancery Guide and para H2.15 of the Commercial Court Guide provide that the procedure to be adopted at a meeting is a matter for the experts themselves, not the parties or their legal representatives.

143  PD 35, para 9.4.

144  CAT Guide, para 7.66.

145  For example, BSkyB and others v Ofcom, Case No 1151/3/3/10. Imperial Tobacco Group plc and others v OFT, Case Nos 1160-65/1/1/1. Generics UK Limited v Competition and Markets Authority, Order of the CAT dated 17 November 2016 (see para 7). See also (T) Agents’ Mutual Ltd v Gascoigne Halman Ltd (t/a Gascoigne Halman) and Agents’ Mutual Ltd v Moginie James Ltd, and the CAT’s Order (Pre-Trial Review) dated 15 December 2016.

146  Referred to in para 7.66 of the CAT Guide: Genzyme v OFT [2005] CAT 32; [2006] Comp AR 195 and the transcript of the hearing in that case on 13 October 2004.

147  CAT r 21(1)(a) and r 55(1)(a).

148  Guidance for the Instruction of Experts, para 77.

149  Ibid, para 79.

150  CMC dated 8 April 2011; see transcript at p 4.

151  This was the approach adopted, for example, in BSkyB and others v Ofcom, Case No 1151/3/3/10.

152  CPR r 35.12(4), para 76 of the Guidance for the Instruction of Experts, and para 7.66 of the CAT Guide.

153  CPR r 35.12(3).

154  [2008] EWHC 1978.

155  Ibid, paras 203–208.

156  Guidance for the Instruction of Experts, para 80.

157  Ibid.

158  Chancery Guide, para 8.15 and Commercial Court Guide, para H2.22.

159  For a fuller description of ‘hot-tubbing’ see ch 58 (para 4.17) of Lord Justice Jackson’s Review of Civil Litigation Costs—Preliminary Report, published in May 2009 and available at <www.judiciary.gov.uk>. A video of a mock ‘hot tub’ in an Australian competition case can be found at <www.clen.law.unimelb.edu.au>.

160  QCMA ((1976) ATPR 40-012). It is now widely used in Australian courts. For an example of the directions associated with the use of a hot tub by the Australian Competition Tribunal see Qantas Airways ((2004) ACompT 9). It is also permitted under the rules of the High Court of New Zealand and New Zealand Competition Tribunal (for an example of its use in a competition case, see Todd v Shell (NZHC 2010)), the Canadian Competition Tribunal, and more recently the Canadian Federal Court.

161  For example, the practice adopted in New Zealand does not allow experts to ask questions of each other, whereas the practice adopted in Australia does.

162  See Chapter 38, Section 3, paras 3.23–3.24 of Jackson LJ’s Review of Civil Litigation Costs: Final Report, available on the <www.judiciary.gov.uk> website.

163  Manchester Concurrent Evidence Pilot Interim Report, available on the <www.judiciary.gov.uk> website.

164  A total of eighteen cases had been identified as suitable, but of those fifteen settled prior to trial.

165  The necessary amendment was made to the Guide to the Technology and Construction Court, 2nd Edition, 2nd Revision published in October 2010.

167  Ibid, para 81.

168  [2016] EWHC 253 (Ch).

169  Para 47.

170  Generics (UK) Ltd v CMA [2018] CAT at para 73.

171  Unwired Planet International Ltd v Huawei Technologies Co Ltd [2017] EWHC 711 (Pat), at para 58.

172  BritNed Development Ltd v ABB [2018] EWHC 2616 (Ch) at para 75.