The Court of Appeal has held that a court is not bound to accept the evidence of an expert witness even if it has not been controverted by other expert or factual evidence and the expert was not cross-examined. In doing so, it overturned the High Court’s ruling that, provided such a report complies with the procedural rules on expert evidence, the court is not entitled to subject it to the same kind of analysis and critique as if it were evaluating a controverted report: Griffiths v TUI (UK) Ltd [2021] EWCA Civ 1442.

The court held that there is no bright line distinction in this regard between controverted and uncontroverted experts’ reports. As with all witness evidence, it is the court’s function to assess whether the evidence in an expert’s report is sufficient to enable the party relying on it to meet the required standard of proof on the relevant issue. The court is not a “rubber stamp” for uncontroverted evidence and there is no rule preventing it from scrutinising and ultimately deciding to give little or no weight to such evidence. Further, unless the expert’s veracity is challenged, it is not inherently unfair for the expert not to be given a chance to respond to criticism of their evidence in cross-examination or otherwise.

It is therefore technically open to an opposing party to elect not to serve expert evidence in reply nor seek to cross-examine the expert, and instead wait to challenge the report for the first time in closing submissions (provided it is not questioning the credibility of the expert). However, as the court noted, that may be a high risk strategy. It is not one most commercial parties would be likely to adopt unless perhaps the claim value is small and therefore the cost of expert evidence may be disproportionate.

Conversely, a party who has served an expert’s report which is uncontroverted should not assume that the opposing party will not challenge the evidence in closing submissions, or that the court will necessarily accept the evidence. The onus is on the party submitting the evidence to make sure all relevant matters are covered and (assuming that party bears the burden of proof on the relevant issue) the content of the report is sufficient to satisfy the burden of proof.

Background

The proceedings concerned a claim against a travel company in respect of acute gastroenteritis suffered by the claimant on an all-inclusive holiday to Turkey, allegedly caused by unsafe food consumed at the hotel.

Both parties had permission to serve expert reports from a gastroenterologist and from a microbiologist (the latter dealing with causation). The defendant did not serve any expert evidence. The report from the claimant’s expert microbiologist (Professor Pennington) was very brief. It concluded that, on the balance of probabilities, the claimant acquired his illness following the consumption of contaminated food or fluid from the hotel. The expert provided written responses to questions from the defendant pursuant to CPR Part 35 (which responses were later said to be deficient) but the defendant did not seek to cross-examine him.

Her Honour Judge Truman accepted the claimant’s factual evidence as to his symptoms, what he had eaten and where, and the relevant dates of each. However, she dismissed the claim on the basis that causation had not been proved. Her judgment set out what she considered to be a number of deficiencies in Professor Pennington’s report, which she described as “minimalist”. Those deficiencies included “a huge gap in reasoning” between various biological facts stated by the Professor and his conclusion that the hotel was at fault, and the lack of a clear train of logic for excluding the possibility of blame being attributed to two non-hotel meals or to causes unrelated to lack of hygiene or to food at all.

On appeal, the High Court (Martin Spencer J) overturned that decision and entered judgment for the claimant on the basis that the court had been bound to accept Professor Pennington’s evidence. He considered that the court was not entitled to subject an uncontroverted expert report

“to the same kind of analysis and critique as if it was evaluating a controverted or contested report, where it has 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.”

Decision

A majority of the Court of Appeal (Asplin LJ and Nugee LJ, Bean LJ dissenting) allowed the appeal and reinstated the order of HHJ Truman.

Majority judgment

The majority held that Martin Spencer J had erred in concluding that an expert’s report which complies with CPR Part 35 and is uncontroverted cannot be impugned in submissions and ultimately rejected by the judge. The authorities do not support the bright line approach he adopted between controverted and uncontroverted evidence. The appropriate approach in any case will depend upon all of the circumstances, the nature of the report itself and the purpose for which it is being used in the claim.

Asplin LJ noted that where the evidence was that of a joint expert, which went to the relevant issues and contained logical conclusions, it would be rare that it should be rejected, and cogent reasons for doing so would be required. The same would be the case where two experts had produced coherent reports covering the relevant issues and were agreed. However, there is no rigid rule that prevents the court from considering the content of an uncontroverted report.

The court also rejected the defendant’s argument that, if a party intends to criticise an expert’s reasoning, fairness demands that they avail themselves of all the means available under the CPR to do so, and so must put in contrary evidence and/or put the points to the expert in cross-examination to give the expert the opportunity to answer them. To the extent that the defendant relied on the well-known principle set down in Browne v Dunn (1893) 6 R 67 HL and subsequent cases, that was not relevant here as that line of authority is concerned with cases where a party is challenging a witness’s credibility and the truth of their evidence. In this case, Professor Pennington’s credibility was not in issue.

The court saw nothing unfair in a party reserving its criticisms of an expert report until closing submissions if it chooses to do so, as long as the expert’s veracity is not challenged. It is for the party who relies on expert evidence to make sure the content of the report is sufficient to satisfy the burden of proof on the issue to which it is directed. They are not entitled to require the opposing party to highlight deficiencies or gaps in that evidence so that they have an opportunity to remedy them. The court observed that “it may be a high risk strategy” for the opposing party to choose to neither adduce contrary evidence nor seek to cross-examine the expert, but there is nothing impermissible about it.

Minority judgment

In dissent, Bean LJ “profoundly disagree(d)” with the majority’s conclusion 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 there is nothing inherently unfair in that procedure.

He considered it a trite proposition that a party is required to challenge in cross-examination the evidence of any witness of the opposing party if they wish to submit to the court that the evidence should not be accepted on that point. He did not accept that that principle is confined to cases such as Browne v Dunn, where it is submitted that the witness is lying.

Bean LJ agreed with the majority that Martin Spencer J was wrong to hold that the role of the court falls away and the court is bound to accept expert evidence where it is not controverted by other expert or factual evidence. However, in his view, a judge is generally bound to accept the evidence if it is not controverted “and the opposing party could have cross-examined the expert on the point but chose for tactical reasons not to do so” (emphasis in original). He noted that there may be exceptional cases where no conflicting evidence or cross-examination is necessary, such as where there is an obvious mistake on the face of the expert’s report, but this case was not in his view exceptional in any sense.

For those reasons, Bean LJ considered that the claimant did not have a fair trial of his claim and the case amounted to litigation by ambush. He would have dismissed the appeal.

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