Supreme Court clarifies position on uncontroverted evidence - TUI Ltd v Griffiths

United Kingdom

The Supreme Court has now clarified the position in relation to uncontroverted evidence.

After nine years, TUI Ltd v Griffiths [2023] UKSC 48 has reached a conclusion which most practitioners were expecting. Subject to certain important exceptions, evidence which is not agreed must be challenged by cross-examination. This is an essential feature of our adversarial system and is required to ensure fairness to the parties, the witness (whose evidence a judge is invited to reject) and the court.

Although Griffiths concerned expert witness evidence, the principle established applies to the evidence of any witness, expert or not.

Background – Mr Griffiths gets ill on holiday

Two days into an all-inclusive package holiday in Turkey purchased through the defendant, the claimant became unwell with gastric symptoms. Following an admission to hospital, a diagnosis of acute gastroenteritis was made, with tests showing parasitic and viral pathogens. The claimant consumed all of his food and drink at the hotel, apart from a meal at the airport and another at a local town.

Proceedings were issued and the defendant denied liability. The case was allocated to the multitrack.

The claimant relied upon expert evidence from a gastroenterologist, Dr Thomas, and a microbiologist, Professor Pennington. Professor Pennington’s expert opinion was that the likely cause of the claimant’s gastric illness was contaminated food or drink from the hotel.

Despite having permission to obtain evidence from a gastroenterologist and a consultant microbiologist, no expert evidence was served by the defendant. Part 35 questions were, however, put to Professor Pennington, which he answered.

From Trial to the Court of Appeal

The case proceeded to trial. Professor Pennington’s report and Part 35 replies were put before the court, but the expert was not called to give oral evidence and so was not subject to cross-examination.

Given both the absence of cross-examination and contrary expert evidence from the defendant, Professor Pennington’s evidence on the causation of the claimant’s illness was uncontroverted. The defendant did, however, make criticisms of his evidence in a skeleton argument filed shortly before trial and in counsel’s closing submissions.

The trial judge accepted the claimant’s evidence on what he had eaten, when he began suffering from the gastric symptoms and the symptoms from which he had suffered. However, it was found that there were deficiencies with Professor Pennington’s evidence in respect of causation. The report was described as “minimalist”. The judge concluded that the claimant had failed to prove his case as his expert evidence was insufficient to prove causation.

The claimant appealed to the High Court, which allowed the appeal.

The defendant then appealed to the Court of Appeal, which found for the defendant by a majority, Bean LJ dissenting.

The majority considered that there was no rule to prevent an uncontroverted, CPR compliant, expert’s report from being rejected by the court. It was open to the trial judge to conclude that the uncontested report was insufficient to satisfy the burden of proof in relation to causation and that it was not unreasonable for a party to seek to challenge evidence in closing submissions, without adducing evidence to the contrary or challenging the expert in cross examination. It was not for the opposing party to make good deficiencies in the claimant’s evidence.

In dissenting, Bean LJ stated that it was wrong for a party to withhold its criticisms until closing submissions, likening it to litigation by ambush and stating that he considered that the claimant did not have a fair trial.

The Supreme Court – establishing a general rule but highlighting important exceptions

The claimant successfully appealed to the Supreme Court.

The Supreme Court considered that making closing submissions attacking an expert’s evidence was neither fair nor sufficient. Professor Pennington’s report may have been “terse” and lacking in certain respects, but it did provide reasonable justification for the expert’s conclusion on causation. It was not a mere expression of opinion. His evidence ought to have been tested by cross-examination.

With reference to a statement in Phipson on Evidence, that a party is required to challenge on cross-examination the evidence of any witness of the opposing party if it wishes to submit to the court that that evidence should not be accepted, the Supreme Court found that the claimant had been denied a fair trial. Maintaining the fairness of the trial included ensuring fairness to the witness whose evidence was being impugned and enabling the judge to make a proper assessment of all the evidence. Cross-examination gave the witness the opportunity to explain or clarify his or her evidence. That principle was not limited to cases in which the witnesses’ honesty was being impugned, but rather was of general application. 

It is important, however, to recognise that the Supreme Court did not find this to be an absolute rule. It was to be regarded as a general principle, but there would be circumstances in which it should not apply. 

Examples provided by the court were:

  • the matter to which the challenge is directed is collateral or insignificant and fairness to the witness does not require there to be an opportunity to answer or explain;
  • the evidence of fact is manifestly incredible, and an opportunity to explain on cross-examination would make no difference;
  • the expert report contains a “bold assertion of opinion” without reasoning to support it (“bare ipse dixit”), although this should be distinguished from reasoning which appeared inadequate and was open to criticism for that reason;
  • an obvious mistake on the face of the expert report;
  • the witnesses’ evidence of the facts are contrary to the basis on which the expert expressed his or her view in the expert report;
  • where an expert has been given a sufficient opportunity to respond to criticism of, or otherwise clarify his or her report, for example, through questions under CPR Part 35.6;
  • a failure to comply with the requirements of CPR PD 35.

It was found that none of the exceptions applied in this matter. Although Part 35 questions had been put to the expert in Griffiths, they were not sufficient to properly put the claimant on notice of the challenge being made to the evidence. They had not provided opportunity for the expert to explain his evidence, sufficient to negate the need for cross-examination.

In dismissing the defendant’s argument that requiring cross-examination would lead to a disproportionate increase in legal costs, the Supreme Court observed that, in low value cases, where deficient medical evidence is relied upon, a defendant had the opportunity to address the deficiencies through targeted Part 35 questions, clearly setting out the challenges and providing sufficient opportunity for the expert to respond, thereby keeping the costs associated with defending matters of this nature proportionate. 


The Supreme Court has clarified the way in which disputed evidence, not only expert evidence, should be handled. Parties must challenge clearly and allow sufficient opportunity for response.

This is consistent with the requirement that cases are dealt with justly. Under the CPR, however, cases must not only be dealt with justly but also at proportionate cost. Requiring experts in low value claims to give oral evidence at trial significantly increases costs. The clear instruction from the Supreme Court is that parties must ensure that full and effective use is made of Part 35 Questions in such cases, rather than raising challenges at the end of trial.

The exceptions cited are wide-ranging, however. It is not at all difficult to imagine that arguments will arise over whether, for example, an expert report contains the bare assertion of opinion without adequate justification, or whether a party’s Part 35 Questions provided an expert with adequate opportunity to address criticisms of the evidence.

As is so often the case, firmly closing one area of dispute may prove to result in the creation of new issues for parties to fall out about. We suspect that the ripples from Griffiths will run on for some time to come.