Expert Evidence and the Ambush Defence –TUI UK Ltd v Griffiths [2023] UKSC 48
Summary; The recent Supreme Court decision in TUI v Griffiths [2023] UKSC 48 goes back to basics and highlights the need for parties to play fair when it comes to challenging evidence, particularly expert evidence, in closing submissions. While it may not lead to experts having to be called more often, it certainly casts a burden on those planning to challenge evidence in submissions to think ahead and plan how a witness, who is not to be called and cross-examined, can be given a fair opportunity to answer, prospectively, criticisms that will be made of them.
The general tenor of the judgment was that where one wishes to attack an expert report (or indeed, any evidence) inclosing submissions, then they ought to play by the rules and give the other side adequate notice of their intentions. This usually involves cross-examining the expert or witness or putting contravening evidence before the court and giving the other side an opportunity to properly respond to it.
Many may think that this is a basic principle of proceedings in England and Wales; so why did the Supreme Court need to consider it and what implications will their judgment have on Civil Proceedings moving forwards?
The Facts – How Did We Get Here?
The factual and procedural history of this matter is set out in the judgment at [1] – [33] per Lord Hodge, with whom the other Justices agreed.
In brief, Mr Griffiths booked a package holiday in Turkey with TUI back in 2014. Whilst on this holiday, Mr Griffiths suffered a ‘serious stomach upset which has left him with long-term problems’. He then decided to sue TUI in August 2017 in the County Court under the Package Travel, Package Holiday and Package Tour Regulations 1992 (SI1992/3288) and Sections 4 and 13 of the Supply of Goods and Services Act 1982.
The County Court – paras [7] –[19]
TUI lodged a Defence that denied that the illness had been caused by food or drink in the hotel where Mr Griffiths was staying, putting him to strict proof on all allegations. The matter was allocated to the Fast Track and each party was given permission to rely upon the reports of two experts: one microbiologist and one gastroenterologist.
Mr Griffiths obtained two such reports, the important report for the purposes of this appeal being that of microbiologist Professor Hugh Pennington. TUI obtained their own microbiologist’s report, but chose not to serve it, leaving Professor Pennington’s report as the only expert report on the major causation issue: what was the likely cause of the infection? Part 35 questions were put to Professor Pennington which he duly answered in the ordinary manner.
TUI did not seek to have Professor Pennington attend the trial for cross-examination, meaning his evidence was uncontroverted when the matter came before the court in June 2019.
However, on the afternoon of the day before the trial, TUI’s counsel filed and served a skeleton argument which criticised Professor Pennington’s findings and argued that the Claimant had not made out his case on causation as a result.
At the trial, HHJ Truman heard the evidence, finding Mr and Mrs Griffiths to be entirely credible witnesses offact; yet she dismissed the claim on the basis of counsel’s submissions on Professor Pennington’s report. The main criticism was that the report did not deal with all the matters required by the Court of Appeal in Wood v TUI Travel PLC [2017] EWCA Civ 11; [2018] QB 927.
Mr Griffiths then appealed this decision to the High Court, arguing that he had not had a fair trial since Professor Pennington’s report was uncontroverted (no evidence having been filed by TUI in response to it), and arguments against the report had only been raised on the day before trial. In short, he was the victim of an “ambush defence”.
The High Court – paras [20] –[25]
The matter came before Martin Spencer J who determined that he had two questions to answer:
(1) Is the court obliged to accept an expert’s uncontroverted opinion even if that pinion is a bare ipse dixit – i.e. a one-line report stating an expert’s conclusion.
(2) If not, in what circumstances could the court be justified in rejecting such evidence?
Martin Spencer J answered this in the negative – if the report were a bare ipse dixit, then the court was not bound to accept it. However, such a report was difficult to imagine in light of Part 35 and the well-publicised duty of experts in preparing such reports.
The learned Judge concluded that a failure to set out the reasoning required by para 3.2(6)(b) of Practice Direction 35might diminish the weight to be attached to the report, but ‘that is not a consideration: that only arises once the report is controverted’ (para 36of Martin Spencer J’s judgment).
The criticisms of HHJ Truman were strong, but Martin Spencer J rejected those as they went to the weight to be attached to the report; such criticisms were irrelevant where the report was uncontroverted as in this case. Accordingly, the appeal was allowed.
The Court of Appeal – paras [26] – [33]
TUI appealed the decision of Martin Spencer J to the Court of Appeal. Asplin LJ and Nugee LJ allowed the appeal, with “that most moderate of judges” (to borrow from Counsel in the Supreme Court) Bean LJ delivering a strong dissenting judgment. The main reasons for allowing the appeal were:
(1) The court was not bound to accept an uncontroverted expert’s report simply because it was compliant with CPR PD 35.
(2) The authorities requiring cross-examination of witnesses related to witnesses being allowed to give an explanation when their honesty or credibility was being impugned. Professor Pennington’s credibility was not in issue; so there was nothing inherently unfair in challenging his expert evidence in closing submissions.
(3) Trial judges had to evaluate all of the evidence, including uncontroverted expert evidence, and decide what weight to give that evidence in reaching their factual conclusions.
Bean LJ objections to this reasoning, were that a party is required to cross-examine the evidence of any witness if it wishes to submit to the court that that evidence should not be accepted. TUI should have challenged Professor Pennington’s conclusions on causation in this way and they had not. At [94] of his judgment he said:
‘[A] judge is generally bound to accept the evidence of an expert if it is not controverted by other expert or factual evidence and the opposing party could have cross-examined the expert on the point but chose for tactical reasons not to do so.’
The Judgment – What is the Law? – paras [36] – [82]
The final appeal to the Supreme Court was allowed unanimously. Lord Hodge, giving the judgment of the Court, stated at [43]that the following paragraph from Philipson on Evidence was correct and summarised a long-standing rule of general application:
‘In general a party is required to challenge in cross-examination the evidence of any witness of the opposing party if he wishes to submit to the court that the evidence should not be accepted on that point. The rule applies in civil cases… In general the CPR does not alter that position. This rule serves the important function of giving the witness the opportunity of explaining any contradiction or alleged problem with his evidence. If a party has decided not to cross-examine on a particular important point, he will be in difficulty in submitting that the evidence should be accepted.’ [Emphasis added].
Lord Hodge expressly addressed at [61] –[68] the question whether this would lead to experts’ being called more often in low value cases, with resultant increase in costs and helpfully outlined the circumstances in which this general rule would not apply, for example:
(1) The matter to which the challenge is directed is collateral or insignificant and fairness does not require the witness to have an opportunity to answer or explain.
(2) The evidence is manifestly incredible and cross-examination would make no difference.
(3) The evidence is a bare ipse dixit – a statement without any reasoning to support it.
(4) There is an obvious mistake on the face of the expert report.
(5) The witnesses’ evidence of fact is contrary to the basis on which the expert expressed their view in the report.
(6) An expert has been given sufficient opportunity to respond to criticism of their report – e.g. in response to focused CPR Part 35questions on a given issue.
(7) A failure to comply with CPR PD 35. Lord Hodge warned that the party seeking to rely on this would be wise to seek directions from the trial judge before doing so.
At [69] Lord Hodge noted that the rule is a ‘flexible one’ and that failing to put a relevant matter to an expert in cross-examination does not put the Judge into a “straitjacket”. Fairness may require the witness to be recalled to answer in some cases, but in others the Judge may deal with the issue by considering what weight to attach to the submission bearing in mind the lack of an opportunity to comment.
The relevant principles were summarised at[70] and can be paraphrased as follows:
(1) The general rule is that a party is required to cross-examine a witness before submitting to the court that their evidence should not be accepted. This is true of witnesses of fact and experts.
(2) The purpose of the rule is to make sure that the trial is fair.
(3) The rationale of the rule includes preserving fairness to the party who has adduced the evidence which is now impugned.
(4) Maintaining fairness includes fairness to the witness whose evidence is being impugned. An expert witness in particular may have a strong professional interest in maintaining their reputation or challenging inadequacy, inaccuracy, or dishonesty.
(5) Maintaining such fairness includes enabling the judge to make a proper assessment of the evidence to achieve justice.
(6) Cross-examination gives the witness the opportunity to explain or clarify their evidence, which is important where dishonesty is alleged. However, there is no principled basis for confining the rule to dishonesty.
(7) The rule is flexible and should not be applied rigidly. Its application depends upon the overall fairness of the trial. Where it is disproportionate to cross-examine at length or where a time limit has been set for cross-examination, those circumstances are relevant considerations to the court’s decision on the application of the rule.
(8) There are circumstances in which the rule will not apply(see above).
Applying those principles to the facts, the appeal was allowed because Professor Pennington’s evidence was uncontroverted, he had set out his reasoning, and the “ambush defence” put forward by TUI meant that Mr Griffiths had not had a fair trial.
Conclusions – What Next?
In future, parties would be well-advised to consider their approach when making submissions that attack the contents of any factual or expert evidence.
Fairness dictates that it is not appropriate for a party to present an “ambush defence” and simply seek to criticise evidence in submissions without any prior indication of the irintention to do so. Usually, a witness should be cross-examined to alleviate the unfairness that arises from that course of action.
An important part of this judgment was [81]which said that the same aim could be achieved without cross-examination where:
‘A defendant can ask focused CPR Pt 35.6questions which articulate clearly the challenge or challenges on which the defendant wishes to make and give the expert evidence the opportunity to explain his or her evidence in response to those challenges, thereby obviating the need to seek the expert’s attendance for cross-examination.’
A return to the rules, and the proper reading of them, may therefore allow a party to impugn an expert’s findings byway of submissions whilst protecting that party from the potential costs consequences of having an expert attend the trial. In practical terms, and from the Bar’s perspective this will be welcome, Tui may put an additional burden on solicitors either to brief Counsel early or to seek advice well before trial if an attack is to be mounted. One suspects (although there is nothing to suggest it was a factor in Tui) one frequent cause of un-signalled attacks on expert witnesses is a fresh pair of eyes (Counsel) seeing a case for the first time shortly before trial and realizing that a challenge should have been made earlier. Tui renders such late changes of direction impossible and in future points that could and should have been made at an earlier stage will either have to remain unput or applications for an adjournment with its attendant costs consequences will have to be considered.
