In Palmer v Mantas [2022] EWHC 90, the judge was faced with a conflict of opinions between experts as to the consequences of the index event on the claimant. The judge dealt first with the psychological evidence.

While commencing with a finding that the defendant expert was helpful and gave genuine and honest answers, and indeed was sympathetic towards the claimant, the judge went on to criticise her. He pointed out that her first report was ‘littered with judgemental and rather scathing comments’ and that the expert’s ‘references to the claimant being “self-pitying” and “histrionic” (which she conceded in oral evidence is a term that she would not have used to describe a man), and the raising of “possible social services risk assessment” required to ensure the claimant’s unborn child was properly safeguarded, were unnecessary and inappropriate.’

The expert, it was noted, stated that she liked to use ‘straightforward language’ and that some of her criticisms of the claimant were stated to be out of genuine concern for her. However, the judge found that ‘the way she expressed herself when criticising the claimant…went beyond language which is appropriate for an expert to employ and suggests a level of unconscious bias, even where there is a lack of belief in the claimant’s case, which she undoubtedly did find (and was entitled to do so)’.

In the judge’s view, the expert also made the mistake of placing undue over-reliance on a single historical event reported in the medical records of consuming copious amounts of alcohol. This was an event to which the claimant was unable to provide a response, and in any event, post-accident she suffered from alcohol intolerance as one of her symptoms. The judge was also surprised that the expert relied upon one event, a failure by the claimant to volunteer that she may have been tired because she had been to Paris for the weekend shortly before her appointment, as being an example of potential dishonesty. These two incidents were supportive of the finding of unconscious bias on the part of the expert.

The judge found ‘an absence of balance’ on the part of the expert in her analysis of the claimant’s personnel records, by failing to draw attention to the many positive aspects of her work record and the views of her colleagues.

Finally, only during the expert’s evidence in court did she confirm that she deferred to the claimant’s expert’s analysis of the claimant’s pre-accident health, and that expert’s assessment that the claimant was presently very unwell and incapable of work.

The upshot was that, while the judge accepted that the expert was not intentionally biased against the claimant, her unconscious bias was such that where there were any differences between her evidence and that of the claimant’s similar expert, the judge preferred the claimant’s expert’s evidence.

The defendant’s problems did not end there.

The defendant’s second expert, a pain consultant, fared little better. The judge recognised that it was open to an expert to disbelieve a claimant’s account of their symptoms in the context of their overall medical records and any other evidence available, but to do so ’needs necessarily a strict and close adherence to their Part 35 duty which should not be departed from, either intentionally or recklessly’. He went on to criticise the expert for being ‘over-zealous in his use of language from the outset’, a concession made by the expert himself in evidence who admitted that, on re-reading his reports, he had ‘winced’ and that he thought he ‘could have been a little bit more reflective and kinder and provided a little bit more range of opinion’. 

He also backtracked on his description of the claimant in surveillance film as being ‘more or less housebound’ to assert that ‘she was more housebound than most people of the claimant’s age’. He inaccurately asserted that another expert had attributed all of the claimant’s ongoing complaints to brain injury, when he had not, as the expert had to concede in evidence. The expert also inaccurately suggested that the opposing pain consultant had based his opinion on the other expert, when in fact three alternatives had been given for the claimant’s condition, only one of which was based on brain injury.

The defendant’s pain consultant had a practice of not considering the claimant’s clinical records ahead of his assessment of (and consultation with) the claimant. This is a practice one comes across from time to time by experts who assert that they do not want to be influenced or biased at interview from having read the history first.  However, as a method it provided no opportunity for the claimant to comment on the contents of these medical records, particularly set against a relatively brief medical history taken orally from the claimant by the expert. He also failed to make reference in reviewing aspects of the evidence to anything which might have been supportive of the claimant’s case.

The judge concluded that there was a significant departure from the expert’s Part 35 duty and a lack of necessary balance.

Independence and objectivity

A court expert is under a duty to help the court on matters within the expert’s expertise (CPR 35.3(1)), and this can only be achieved by being independent and objective. The principle was stated in the Ikarian Reefer (1993), which predated the CPR but on which much of the CPR was based, and which is still good law, thus:

‘An expert witness should provide independent assistance to the court by way of objective unbiased opinion in relation to matters within his expertise.’

The Guidance for the Instruction of Experts in Civil Claims provides at paragraph 11:

‘Experts must provide opinions that are independent, regardless of the pressures of litigation. A useful test of “independence” is that the expert would express the same opinion if given the same instructions by another party.’

Professional rules may also re-enforce this approach. For example, the GMC Guidance for acting as a witness in legal proceedings states at paragraph six:

‘You must make sure that any report that you write, or evidence you give, is accurate and not misleading. This means you must take reasonable steps to check the accuracy of any information you give, and to make sure that you include all relevant information.’

Paragraph 13 provides:

‘You must give an objective, unbiased opinion and be able to state the facts or assumptions on which it is based.’

Recently in Liverpool Victoria Insurance Co Ltd v Zafar [2019] EWCA Civ 392, it was emphasised that an objective, unbiased opinion must be based on a consideration of all material facts, including those that might detract from the opinion and are not in the best interests of the party who has instructed them.

Learning points

  • There is no place in an expert’s report or evidence for emotive or loaded language, let alone potentially sexist language. A report should not contain speculative comment, without putting such comment in its true context and with the facts which support it. Such language is likely to be seen as indicative of bias, intentional or otherwise.
  • Even when the expert forms a strong view that the claimant is lying or manipulative, or simply unreliable, the expert must approach the evidence objectively, setting out the material evidence, putting it in context, being sure to also set out any evidence which could arguably lean the other way, and explaining the reasoning which supports the conclusion reached.
  • The expert should be extremely careful in picking on isolated events in the history to support a more general proposition. Such an isolated event might be supportive of other evidence, but, used on its own, the expert may well give the impression of bias, or indeed of carelessness, unless the expert can make the case that although it is an isolated event it is nonetheless, for good reason, an event the expert considers themselves entitled to draw appropriate conclusions from.
  • It is also poor practice for the expert to rely on an event, or an entry, in the records that is generally adverse to the claimant without giving the claimant the opportunity to comment on it or to explain it. If it is the expert’s practice not to read the records until after interviewing the claimant, then this is a potential weakness in the opinion-making process, unless a subsequent opportunity is given to the claimant to comment before any conclusion is reached by the expert.
  • Balance is called for in the expert’s approach to the evidence at all times. An absence of balance is indicative of bias, even if it is unconscious bias.
  • If an expert changes their opinion, or modifies it significantly, subsequent to providing a written report, then this should be notified to their lawyers at the earliest opportunity, for them to inform the other side. The report should be amended or a further report prepared which explains the reason for the change of opinion (see Guidance paragraph 66). Giving a different or modified report while giving evidence in court is likely to undermine the expert’s evidence more generally and can be suggestive of previous bias or lack of care.
  • An expert will undermine their evidence if they inaccurately state the opinion or the evidence of another expert in the same case. This is either indicative of lack of care, or of bias.

Giles Eyre is a retired barrister and an Associate Member of Chambers at 9 Gough Chambers, London, having practised for many years in the field of injury claims and at the interface of law and medicine.  He continues giving training and presenting workshops for experts on providing effective expert reports and evidence, and on medico-legal issues, in his own right and for training organisations.  He is co-author of Writing Medico-Legal Reports in Civil Claims – an essential guide (2nd edition 2015), and author of Clinical Practice and the Law – a legal primer (October 2018) both published by Professional Solutions Publishing and available through book retailers or from the author, and regularly writes articles on these subjects. He blogs on issues relevant to court experts in civil claims at .

Special Offer: For MAPS experts, ‘Writing Medico-Legal Reports in Civil Claims – an essential guide’ (normal price £69.95) is available at £50.00 and ‘Clinical Practice and the Law – a legal primer’ (normal price £34.95) is available at £19.95. P&P for one book £4.95, £8.95 for both. Offer available only direct from the author by email to More information about the books and reviews are available at

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