The Court of Appeal has handed down a controversial judgment by majority on the ability of a party to invite the court to reject expert evidence, even when the point in issue has not been put to the expert in cross-examination. The minority judgment, from Bean LJ, contains stinging criticism of the majority position, and might pave the way for an appeal to the Supreme Court.
The decision has significant ramifications for all practitioners in fields where expert evidence arises.
The Respondent, Mr Griffiths, took an all-inclusive package holiday with the Appellant travel company, during which he suffered a gastric illness. He alleged that this was the result of consuming contaminated food or drink as part of the all-inclusive deal which he purchased. He claimed damages from the Appellant.
At first instance in the County Court, the Mr Griffiths’ was dismissed, with the judge not being satisfied that his illness was caused, on the balance of probabilities, by contaminated food or drink supplied by the hotel.
The travel company had not provided its own evidence on the issue, but Mr Griffiths had served an expert report from a microbiologist, Professor Pennington. The travel company had not cross-examined him at trial so he gave no oral evidence, but the travel company had made criticisms of his written evidence in closing submissions, inviting its rejection.
In other words, Mr Griffiths’ expert evidence on causation was the only evidence on that matter before the judge. It was not tested in cross-examination at all. Despite this, the travel company criticised it in closing, and the judge rejected it.
The High Court reversed that decision, noting that the evidence of Prof Pennington was “uncontroverted”, meaning unchallenged by any rival evidence on the issue and not challenged through cross-examination.
 “… a court would always be entitled to reject a report, even where uncontroverted, which was, literally, a bare ipse dixit , for example if Professor Pennington had produced a one sentence report which simply stated: “In my opinion, on the balance of probabilities Peter Griffiths acquired his gastric illnesses following the consumption of contaminated food or fluid from the hotel…”
The judge allowed the appeal because:
 “… what the court is not entitled to do, where an expert report is uncontroverted, is subject the report to the same kind of analysis and critique as if it was evaluating a controverted or contested report, where it had to decide the weight of the report in order to decide whether it was to be preferred to other, controverting evidence such as an expert on the other side or competing factual evidence. Once a report is truly uncontroverted, that role of the court falls away. All the court needs to do is decide whether the report fulfils certain minimum standards which any expert report must satisfy if it is to be accepted at all” (Original emphasis).
Consequently, the first instance judge fell into error, the High Court found, and the appeal was allowed.
The Court of Appeal: the majority decision
The travel company appealed, arguing among other matters that the High Court decision misstated the limits of a trial judge’s ability to examine the substance of an expert report which had not been challenged through cross-examination. Its reasoning and conclusions can be examined in such circumstances, it was argued, to establish whether the burden of proof has been met.
In the majority judgment, given by Asplin LJ, a comparison with criminal court handling of expert evidence was made:
 “…The jury must decide a case upon all the evidence in just the same way as a judge in a civil trial. Furthermore, where there is expert evidence which is within the domain of scientific expertise and no challenge is made to it, and there is no rational or proper basis for departing from it, the jury may not do so. In the same way, it is hard to envisage the circumstances in which it would be appropriate for a judge to do so. However, that does not mean that there is a strict rule that uncontroverted evidence must be accepted at face value whatever it says. As Davis LJ noted at  of his judgment [in R v Brennan  1 WLR 2060], the then most recent Crown Court Bench Book stated that where there was no dispute about the findings of an expert, the jury is likely to wish to give effect to them but was not bound to do so if there was good reason to reject them. As Davis LJ stated, this is consistent with the principle that if unchallenged expert evidence is to be rejected then it must be rejected for a reason.”
 “Rather than support the contention that there is a bright line between controverted and uncontroverted expert evidence, it seems to me that Davis LJ’s judgment supports a more nuanced approach. Even in a criminal trial, the jury may reject uncontroverted expert evidence where there is reason to do so…”
Crucially, in allowing the appeal, Asplin LJ went on:
“ … As long as the expert’s veracity is not challenged, a party may reserve its criticisms of a report until closing submissions if it chooses to do so. The defendant is entitled to submit that the case or an essential aspect of it has not been proved to the requisite standard. He cannot be prevented from doing so because some of the evidence is contained in an uncontroverted expert’s report. Furthermore, he cannot be required to file his own contrary expert’s evidence in order to enable the court to weigh the evidence. The judge cannot be prevented from considering the quality of such evidence in order to determine whether the burden of proof is satisfied just because it is uncontroverted. As Judge Truman stated, the court is not a rubber stamp. If it were otherwise, the court would be bound by an uncontroverted expert’s report which satisfied CPR PD 35, even if the conclusion was only supported by nonsense.” (Emphasis added)
Nugee LJ agreed with Asplin LJ and the appeal was allowed.
Court of Appeal: the Minority Judgment
Bean LJ evidently had a very strongly opposing view to the majority:
 “But it is even more trite law that, as Phipson on Evidence puts it:
“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 as it does in criminal. 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 rejected.” (19th edn, 2018, para.12-12).
Throughout my 28 years as a practising barrister this proposition would have been regarded as so obvious as not to require the citation of authority. Certainly we were not shown any authority to the contrary. And I agree with Nugee LJ that there is no special rule for experts.” (Emphasis added)
He went on to express his disagreement with the majority’s position, that only when an expert is being accused of dishonesty, is it necessary to put that accusation to the expert in cross-examination in order to be entitled to rely on it in a closing speech and for the judge so to find:
 “I do not accept that the principle set out in Phipson is confined to cases such as Browne v Dunn, in which it was held that a witness must be challenged in cross-examination if it is sought to allege that the witness is lying. The principle is wider than that, and applies both to lay witnesses and experts. It does not extend to every point of detail in a long witness statement: that is a matter for the discretion and common sense of the trial judge. But here Professor Pennington gave a clear conclusion on the very issue on which he was asked to give an opinion, namely that “on the balance of probabilities Peter Griffiths acquired his gastric illnesses following the consumption of contaminated food or fluid from the hotel”. This could and should have been challenged in cross-examination.”
He evidently had great sympathy for the position of Mr Griffiths, given the outcome, despite his expert evidence not having been subject to any challenge in the witness box, which can only have led him to expect that it was evidence accepted by both parties:
 “Mr Griffiths must be wondering what he did wrong. He instructed a leading firm of personal injury solicitors, who in turn instructed an eminent microbiologist whose integrity has not been questioned. Mr Griffiths and his wife gave evidence at the trial, were cross-examined, and were found by the judge to be entirely honest witnesses. The eminent expert gave his opinion that on the balance of probabilities Mr Griffiths’ illness was caused by the consumption of contaminated food or fluid supplied by the hotel. No contrary evidence was disclosed or called, and the expert was not cross-examined. Yet the Claimant lost his case.”
 “Asplin LJ, with whom Nugee LJ agrees, says at  that “as long as the expert’s veracity is not challenged, a party may reserve its criticisms of a report until closing submissions if it chooses to do so”, and that she can see nothing which is inherently unfair in that procedure. With respect, I profoundly disagree. In my view Mr Griffiths did not have a fair trial of his claim. The courts should not allow litigation by ambush. I would therefore have dismissed TUI’s appeal.” (Emphasis added)
It is not yet known whether the case will proceed to the Supreme Court but given the strength of disagreement between the majority and minority in the Court of Appeal, the chances of permission being granted would appear to be good.
The decision has caused considerable controversy. Restricting the obligation to cross-examine an expert, in order to be entitled to invite the court to reject that expert’s evidence, to situations where dishonesty is alleged, is a major change from what most practitioners considered to be the position before this Court of Appeal decision was handed down.
While a party choosing not to cross-examine and criticising an expert only in closing submissions will be taking a big risk that those submissions will not be accepted, the author’s view is that this decision is nevertheless a serious departure from the principle quoted from Phipson, above, that it is necessary to cross-examine a witness (including an expert witness) if the court is to be invited to reject that witness’ evidence for any reason.
It is difficult not to agree with the minority view, that the approach taken by the majority paves the way for trial by ambush. A party may be unable to predict every criticism which might be made of their expert witness’ evidence such that they can pre-emptively serve evidence in rebuttal. That risk has historically been mitigated by the requirement that an expert have put to him or her such criticisms in cross-examination, so there is at least the opportunity in oral evidence to address them. Parties can now make criticisms of expert witnesses and choose not to give them the opportunity to answer them in cross-examination.
This raises not only the likelihood of ambush, but also risks experts producing longer reports, at great additional cost, to try to address all predicted criticisms which might be made of them.
It remains to be seen whether this decision is clarified or overturned in the near future, but there is likely to be considerable pressure to do so.