Supreme Court clarifies rules over expert and factual evidence in civil claims | Fieldfisher
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Supreme Court clarifies rules over expert and factual evidence in civil claims

David Thorne


United Kingdom

On 29th November 2023 the Supreme Court released its decision in the eagerly anticipated case of TUI UK Ltd (Respondent) v Griffiths (Appellant) [2023] UKSC 48

On 29th November 2023 the Supreme Court released its decision in the eagerly anticipated case of TUI UK Ltd (Respondent) v Griffiths (Appellant) [2023] UKSC 48. After a gastric illness on an all-inclusive holiday in Turkey Mr Griffiths sued TUI, the tour operator, alleging that the illness was attributable to contaminated food and drink consumed at the hotel. Mr Griffiths relied on expert evidence from a microbiologist whose opinion was that the illness was more likely than not caused by contaminated food and / or drink. In this article we examine the decision and consider potential lessons for the approach to expert evidence in adjudication.

The crucial role of expert evidence

Initially, the Judge in the County Court, unpersuaded by the microbiologist's evidence, dismissed Mr Griffith's case but this was subsequently overturned by the High Court. That decision was itself reversed by the Court of Appeal. In June 2023 the Supreme Court unanimously rejected the Court of Appeal's decision.

A key issue concerned the treatment of the expert evidence upon which Mr Griffith's claim relied. The original trial judge accepted TUI's submissions that the microbiologist, Professor Pennington, had given an incomplete explanation for the cause of the illness and had failed to discount other possible causes. TUI's submissions were accepted notwithstanding that it had chosen not to cross-examine Professor Pennington nor provided any contrary expert evidence of its own. The Supreme Court considered this failure as fatal to TUI's defence.

The Supreme Court was concerned with fairness and particularly whether the trial judge was entitled to find that Mr Griffiths had not proven his case on a balance of probabilities when the expert evidence had not been tested by TUI. The Supreme Court considered that the evidence of Professor Pennington was not illogical, incoherent or inconsistent, based on any misunderstanding of the facts, or based on any unrealistic assumptions. Nevertheless, TUI sought to criticise the evidence as incomplete in its explanations and for its failure to expressly discount on the balance of probabilities other possible causes. Importantly, TUI chose to raise such criticisms in the closing stages of the trial when it could have submitted evidence from a microbiologist of its own or at the very least have cross-examined Professor Pennington at a time when at which he could have addressed any such criticism.

The burden of proof, trial requirements, and expert testimony in civil proceedings

The Supreme Court set out a helpful explanation of the law in civil proceedings concerning the burden of proof, the requirements for a fair trial and evidence of fact and expert testimony. The principles are described to have broad application which are flexible depending on the circumstances of the case. The nub of the ruling is that to ensure that fairness prevails "a party is required to challenge by cross-examination the evidence of any witness of the opposing party on a material point which he or she wishes to submit to the court should not be accepted". The principle is not so rigid as to require cross examination of an expert whose evidence is manifestly unbelievable e.g., where an expert says the colour red is blue, because in those circumstances cross-examination would make no difference and the absence of cross-examination could not be said to render the trial unfair.

Parties to complex construction disputes are generally aware of the importance of expert evidence which is typically central to the determination of cases whether in TCC litigation, arbitration or adjudication. However, parties are also subject to acute commercial pressures and adjudication, the most common forum for dispute resolution in the sector, is fast paced with limited time and budget for detailed preparation of considered expert evidence. Time pressed adjudicators may see the Supreme Court's decision as a green light to accept uncontested (or lightly contested) expert evidence at face value in a process that is adversarial rather than inquisitorial. Parties to adjudication should therefore take heed to ensure that they take the time available and deploy sufficient resources to address the other party's expert evidence however speculative and flawed such evidence may appear. Ideally such evidence should be contested by an opposing expert or, at the very least, in early submissions which allow the opposing expert an opportunity to respond to the criticism.

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