Landmark UK Supreme Court decision underscores significance of cross-examination in expert witness evidence fairness.

Citation: [2023] UKSC 48
Judgment on


In the landmark decision of TUI UK Ltd v Griffiths [2023] UKSC 48, the Supreme Court ventured into the debated territory of the fairness of a trial as it concerns expert witnesses’ evidence in civil litigation. The key topics broached within the case, including the scope of cross-examination and the reliance on uncontroverted expert evidence, are of particular significance to legal professionals practising within the United Kingdom.

Key Facts

Mr. and Mrs. Griffiths, along with their son, experienced a tumultuous package holiday due to Mr. Griffiths falling ill, purportedly because of the hotel’s food or drink. Consequently, Mr. Griffiths filed a claim against TUI UK Ltd under relevant consumer and services legislation. At the crux of this case was whether the trial was fair when the travel company, TUI, successfully persuaded the trial judge to dismiss Mr. Griffiths’ claim based on alleged deficiencies in his expert’s report—despite not challenging the expert’s evidence by cross-examination or presenting a contending expert report.

The pivotal legal principles deliberated within this appeal were crystallized around the rule commonly referred to as stemming from Browne v Dunn (1893), which dictates that a party should confront a witness during cross-examination about points it intends to dispute. The following core legal precepts were reaffirmed and clarified:

  1. Adversarial System: The judge must maintain a fair trial, but the contriving of issues for determination is predominantly left to the parties.

  2. Expert Evidence and Reasoning: The validity of an expert’s opinion is largely based not on the conclusion it arrives at, but on the reasoning that supports it. A bare statement or a bare “ipse dixit” is not typically deemed persuasive or acceptable.

  3. Fairness and Rule in Browne v Dunn: The rule mandates cross-examination to contest a witness’s evidence and extends beyond the premise of honesty, engulfing any material challenge to the evidence’s integrity.

  4. Exceptions to the Browne v Dunn Rule: The rule is not absolute, and exceptions include circumstances where the matter is trivial, the evidence manifestly incredible, or there is an innocent mistake in the expert report.

The analysis hinges significantly on the landmark cases of Kennedy v Cordia (Services) LLP [2016] UKSC 6; [2016] 1 WLR 597 and Chen v Ng [2017] UKPC 27.


The Supreme Court decisively concluded that the trial had not been fair to Mr. Griffiths, as the criticisms leveraged against the expert’s report were not the subject of cross-examination nor sufficiently flagged to Professor Pennington. Consequently, the failure to cross-examine an expert witness on an inadequately reasoned report, particularly when no contending evidence is offered, cannot be employed to extinguish a claim.

The court restored Mr. Griffiths’ claims on the balance of probabilities, drawing from Professor Pennington’s report and responses, coupled with the factual findings of the trial judge. In doing so, it disavowed both the trial judge’s and the Court of Appeal’s majoritarian restraints on the applicability of the rule in Browne v Dunn.


TUI UK Ltd v Griffiths illuminates the judicial stance that when an expert witness is not cross-examined on points critical to the case’s outcome, and these points are then used to attack the witness’s report in submissions, such a trial cannot be deemed fair. This ruling reinforces the importance of cross-examination within the adversarial system, underscoring it as not just a tool for fairness to the witness, but as a fundamental mechanism to ensure the integrity of the court process itself. Additionally, the clarification and application of exceptions to the Browne v Dunn rule are pivotal, showcasing the rule’s flexibility and the nuanced approach necessary in its application. This case serves as a cautionary tale for practising lawyers, emphasizing the need for meticulous adherence to procedural fairness, particularly when dealing with expert evidence in civil trials.

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