TUI UK Ltd v Griffiths [2023] UKSC 48

Mr Griffiths contracted gastroenteritis during a package holiday in Turkey. His expert witness opined the illness was caused by hotel food. The defendant did not cross-examine the expert but criticised the report in closing submissions. The Supreme Court held this was unfair and allowed the appeal, establishing that expert evidence must generally be challenged by cross-examination.

Facts

Mr Griffiths, his wife and son took a package holiday to Turkey organised by TUI UK Ltd. During their stay at an all-inclusive hotel, Mr Griffiths suffered severe gastroenteritis which has left him with long-term health problems. He sued TUI under the Package Travel Regulations 1992 and the Supply of Goods and Services Act 1982. At trial, Mr and Mrs Griffiths gave unchallenged factual evidence, and Mr Griffiths relied upon expert evidence from Professor Pennington, a microbiologist, who opined that on the balance of probabilities the illness was caused by contaminated food or fluid consumed at the hotel.

Evidence and Trial Conduct

TUI chose not to serve its own expert evidence on causation and did not require Professor Pennington to attend for cross-examination. Instead, TUI’s counsel challenged the adequacy of Professor Pennington’s reasoning only in closing submissions, arguing deficiencies in the report meant the claimant had failed to prove his case. The trial judge accepted these criticisms and dismissed the claim.

Issues

The principal issues before the Supreme Court were:

• What is the scope of the rule, based on fairness, that a party should challenge by cross-examination evidence it wishes to impugn?
• Does this rule extend to attacks on the reasoning of an expert witness?
• Was there unfairness in how the trial was conducted?

Judgment

The Supreme Court unanimously allowed Mr Griffiths’ appeal. Lord Hodge delivered the judgment, with which all other Justices agreed.

The Rule in Browne v Dunn

The Court confirmed the long-established rule stated in Phipson on Evidence:

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.

Lord Hodge emphasised that this rule applies to both witnesses of fact and expert witnesses, and is not confined to challenges to a witness’s honesty. The rationale is the overall fairness of the trial:

The purpose of the rule is not only for the benefit of the witness but is to ensure the overall fairness of the proceedings for the parties.

Application to Expert Evidence

Citing Kennedy v Cordia (Services) LLP, the Court stressed that an expert must explain the basis of their opinion:

An expert must explain the basis of his or her evidence when it is not personal observation or sensation; mere assertion or bare ipse dixit carries little weight… such evidence is worthless.

However, the Court distinguished between a bare ipse dixit (which is worthless) and reasoning that, while terse or incomplete, nonetheless provides a logical basis for the expert’s conclusion. Professor Pennington’s report fell into the latter category.

Fairness of the Trial

The Court held that TUI’s approach—failing to cross-examine the expert and raising detailed criticisms only in closing submissions—was unfair. Lord Hodge stated:

In the absence of a proper challenge on cross-examination it was not fair for TUI to advance the detailed criticisms of Professor Pennington’s report in its submissions or for the trial judge to accept those submissions.

The Court agreed with Bean LJ’s dissent in the Court of Appeal:

Mr Griffiths did not have a fair trial. The courts should not allow litigation by ambush.

Exceptions to the Rule

The Court identified circumstances where the rule may not apply, including: collateral or insignificant matters; manifestly incredible evidence; bare ipse dixit without reasoning; obvious mistakes on the face of a report; evidence based on incorrect assumptions; where an expert has been given sufficient opportunity to respond through other means; and serious failures to comply with CPR PD 35.

Implications

This judgment reinforces the fundamental principle of fairness in adversarial proceedings. Parties cannot lie in wait and ambush expert witnesses with criticisms raised only in closing submissions when they have declined to cross-examine. The decision provides important guidance on:

• The scope and application of the rule in Browne v Dunn to expert evidence
• The distinction between a bare ipse dixit and inadequately reasoned expert evidence
• Practical methods for challenging expert evidence proportionately, including focused CPR Pt 35.6 questions

The judgment preserves the integrity of the CPR framework for expert evidence whilst ensuring that experts are given fair opportunity to explain their reasoning before their evidence is rejected.

Verdict: Appeal allowed. The Supreme Court held that Mr Griffiths did not receive a fair trial. Having made its own assessment of the uncontroverted evidence, the Court concluded that Mr Griffiths had established his case on the balance of probabilities that the illness was caused by contaminated food or fluid consumed at the hotel.

Source: TUI UK Ltd v Griffiths [2023] UKSC 48