UK Supreme Court ruling clarifies fair treatment of expert evidence at trial

The case concerned the fair treatment of expert evidence in civil proceedings, where the expert report is not challenged whether in writing, via a counter expert report or in cross-examination, and provides important clarifications for parties in litigation. Litigation expert Nicola Seymour of Pinsent Masons said that it is particularly relevant in low value cases where defendants may be seeking to save costs by not adducing their own expert evidence nor calling for the claimant’s expert to be cross-examined at trial.

“The judgment strongly demonstrates that a party is not able to sit back and reserve its criticisms of the expert’s evidence for closing submissions, by which time the expert would be denied the opportunity to respond,” said Seymour.

“The principle of fairness requires experts be given the chance to face and address challenges to their evidence. This does not necessarily need to be an expensive or drawn-out process requiring a counter expert to be instructed and report produced with all experts giving evidence at trial; specific written questions could serve this purpose, or focussed cross-examination at trial,” she explained.

The underlying dispute in the case was between tour operator TUI and its customer, Mr Griffiths, who fell sick during his all-inclusive holiday provided by the company. Griffiths sued TUI for breach of contract and relied on expert evidence to prove the cause of his sickness. TUI did not file its own expert evidence or seek to cross-examine the Griffiths’ expert witness at trial, but criticised the expert report as poorly reasoned and unreliable in closing submissions. Griffiths lost in the initial trial, with the judge siding with TUI and deciding that he did not meet the civil standard of proof as the expert’s evidence was unsatisfactory.

Griffiths appealed and the High Court overturned the trial judge. TUI appealed again, resulting in the Court of Appeal (COA) with a 2-1 majority restoring the trial judge’s ruling. On 29 November, the Supreme Court unanimously rejected the COA’s ruling, confirming that Griffiths did not have a fair trial because “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.”

A particular emphasis of the Supreme Court ruling, according to Seymour, is that where the evidence addressed an issue that is fundamental to a claim, such as causation in this instance, a party is not able to wait until closing submissions to assert that the evidence is insufficient to discharge the burden of proof,  especially in circumstances where a party had opportunities to challenge the evidence throughout the proceedings and trial.

Another significant implication of the judgment is that it provides several scenarios in which a party may not be required to challenge the evidence of the opposing party via cross-examination in order to submit that such evidence should not be accepted.  

“This will serve as useful guidance for practitioners when determining the strategy of a case and also for those instructing experts to ensure that the final report and response to written questions does not fall foul of any such scenarios,” said Seymour.

One potential scenario referred to in the judgment was if an expert has been given a reasonable chance to respond to any challenges or criticisms of their report - for example, by way of focussed CPR 35.6 questions by opponents - and failed to provide a satisfactory response.

The judgment has also clarified that the rule is not rigid in this respect, and every case will be assessed by the individual facts and circumstances. “So if it would be disproportionate for cross-examination to take place, this should be borne in mind when applying the rule,” said Seymour.