Expert Evidence – Lessons Learnt from 2025 - Part One

In the first part of a two-part series, Marc Harries and Emma Hague, co-chairs of Clyde & Co’s Expert Subject Matter Group, highlight five key judgments in which issues concerning expert evidence were directly addressed.

LB Croydon v D (Critical Scrutiny of the Paedeatric Overview) [2024] EWFC 438 (20 September 2024)

The issue – the expert conceded parts of her evidence were "appalling".

“There were multiple examples of [the expert’s] lack of "due diligence" in the preparation of her report, addendum report, and in terms of her preparation for and participation in the experts' meeting for which she apologised”.

In this family case, the expert paediatrician’s report was said by the judge to be “subjective, closed minded and disbelieving of the parents’ account”. During her detailed and forensic cross examination, described by the judge as a “nothing short of a demolition” of her evidence, she conceded parts of her evidence were appalling. The case involved twins and the fundamental error running through the whole of her evidence was that she misidentified and confused the twins. Her approach in this case was “a cause for serious concern”. The professional medical evidence was “flawed, factually inaccurate and lacking in enquiry and analysis”. The judge concluded this case “demonstrates the importance of advocates with a detailed knowledge of the case and the facts being able to robustly and critically cross examine experts and fully explore their client's case”.

Dobson v Chief Constable of Leicestershire Police [2025] EWHC 272 (KB) (07 February 2025)

The issue – one expert’s experience and knowledge versus another expert’s internet search.

“It was pointed out to [the expert] in cross examination that the website he consulted (which he very properly set out in the joint report) shed no light on the proper approach to be followed”.

The claimant’s claim was on the basis that the defendant failed in his duties towards the claimant because he was released (after arrest) with insulin and syringes and without any real or effective mental health assessment. The claimant later took an overdose of insulin resulting in life changing injuries. 

Both experts were invited to express a view on the claimant’s mental health during the period of his detention. The defendant’s expert was found to have “relevant experience of the matters in respect of which he was giving evidence” whereas the claimant’s expert’s experience was in a different area of psychiatry. When asked to express a view on the circumstances that would trigger a mental health assessment the defendant’s expert based his response on his own experience and knowledge. The claimant’s expert had conducted an internet search. In cross examination it was pointed out that the website he consulted shed no light on the proper approach to be followed when a person was detained in police custody. The expert said he had conducted the search as he was looking for “a clear definition”.  

Young v Downey [2025] EWCA Civ 177 (28 February 2025)

The issue – the trial judge’s personal opinions overrode the expert’s clearly reasoned evidence.

“The judge was impermissibly allowing his own inexpert opinions about the mental capabilities of a 4½ year child to influence his evaluation of [the expert’s] evidence”.

On appeal, the trial judge’s decision on the facts was found to be wrong and required reversing. He had rejected an expert psychiatrist’s written and oral evidence on the basis of his own views. The trial judge’s opinions regarding a four-year-old claimant and her mental understanding “were of an expert nature and contradicted the expert evidence without any proper foundation to do so”. The expert’s evidence should have been accepted and the judge should have held that the claimant’s psychiatric injuries were caused by the events that she witnessed.

Alame & Ors v Shell PLC & Anor [2025] EWHC 1539 (KB) (20 June 2025)

The issue – the claimants’ criticisms of the defendant’s expert were “unfounded and unhelpful”

“If the claimants really were of the view, for whatever reason, that [the defendant’s expert] could not properly assist the court, then it would have been more useful, and more consistent with the overriding objective, for that to have been raised and determined at a case management hearing before trial”.

In this case the claimants suggested the judge should reject the defendant expert’s evidence in its entirety. Serious allegations were made regarding his honesty and proprietary of his conduct as an expert witness. It was alleged he had wilfully concealed a relevant recent case, however the judge found it was a regrettable oversight. It was rejected this was deliberate, or that the expert had wrongly concealed his involvement when giving evidence in another case. 

The defendants also attempted to “minimise the weight of opinions expressed” by one of the claimant’s experts. This was on the basis the expert was “too interested in telling this court how the law in Nigeria should be, rather than in assisting with how it is”.

It was held by the judge that “experts are human beings” and “will have developed interests and opinions, particularly in areas of law in which they practise frequently”. That does not prevent them from seeking to assist the court in accordance with the requirements set out in CPR Part 35.

DHV v Motor Insurers' Bureau (Rev1) [2025] EWHC 2002 (KB) (31 July 2025)

The issue – the claimant’s expert had not previously given evidence in a UK court.

“The hallmarks of being a reliable and persuasive expert do not change, making every allowance for an alien forum and the pressure of court proceedings”.

In critical respects the judge found the claimant’s accident reconstruction expert’s evidence was not reliable, consistent or convincing. A number of reasons were given including: her original report contained errors; she fundamentally changed her position about the speed of the vehicle; she was prepared to offer opinions on topics she had no sufficient qualifications to give; she did not answer questions directly and often digressed unhelpfully. 

The claimant’s expert on Spanish law was also found to be an unsatisfactory witness. This unsatisfactoriness ranged from simple factual matters such as the number of times she had testified in English proceedings to her persistent attempt to deny she had copied parts of a colleague's expert report. She was described by the judge as approaching “the case at times more as an advocate for the party instructing her rather than an independent arms-length expert.”

Emma Hague and Marc Harries are co-chairs of Clyde & Co’s Expert Subject Matter Group. They were assisted in producing this piece by Lisa Williams, Knowledge Lawyer.