REUTERS | Lucy Nicholson

Judge warns against unconscious bias: Palmer v Mantas and another

On 20 January 2022, Anthony Meltzer QC handed down a judgment following a 12-day trial in November 2021, awarding the claimant damages in excess of £1.6 million for her minor traumatic brain injury. But of particular significance to instructing solicitors and expert witnesses, were his comments regarding the conduct of two of the experts for the defence, warning them against forming opinions of the claimant that suggest a level of unconscious bias.


The claimant’s claim arose out of a road traffic incident on 15 June 2014 when the first defendant drove into the rear of the claimant’s stationary car on the M25 motorway.  Although the first defendant was driving the car at high speed (estimated as being between 50 and 70 miles per hour), the claimant did not appear to suffer immediate significant head injury (although she did seek medical treatment from lesser but concerning symptoms) and returned to work full-time within a relatively short period of time.

It was not until three years after the accident that the claimant stopped working altogether and started displaying many different physical and neurological arguments. These symptoms were documented in a voluminous amount of evidence for the trial, including 22 medico-legal examinations over five years, six witness statements and three schedules of loss.

Liability was admitted and the trial proceeded in respect of causation and quantum, with the second defendant alleging that the claimant had not been entirely honest with the numerous experts she had seen in relation to the full extent of her activities and holidays and had made omissions in her early witness statements about her true level of function.

The claimant sought £2.2 million in damages whereas the first defendant’s insurer was prepared to concede only £5,407.


The judge rejected the second defendant’s arguments, setting out several reasons why, in this case, the claimant’s inconsistences could be explained and did not point to a finding of fundamental dishonestly.

This blog, however, will not focus on the details of this finding, but on the judge’s ancillary observations and critique of two of the medical experts called on behalf of the defendant and their approach to assessing the claimant.

Critique of experts

With regards to one expert, the judge stated that her first report was “littered with judgemental and rather scathing comments” with reference to the claimant being “self-pitying” and “histrionic”. He also stated that the expert’s raising of a “possible Social Services risk assessment” required to ensure the claimant’s unborn child was properly safeguarded, was “unnecessary and inappropriate”.

Meltzer then went on to refer to the case of Mustard v Flower and Direct Lane, commenting that, although the expert was entitled to express a lack of belief in the claimant’s case and criticise the claimant’s actions accordingly, the level of language used “went beyond language which is appropriate for an expert to employ and suggests a level of unconscious bias”. In addition, he compared the expert’s evidence with another expert in the case, stating that he noticed the former’s absence of balance in placing more reliance on small, negative details in the claimant’s medical records and what she volunteered in her statement than other positive aspects of her work records and the views of her colleagues. He found this to be “concerning” and commented on his difficulty in being unable “to safely rely upon her expertise where it differed from [the other expert] because of what [he] perceived to be unconscious bias” (paragraph 79, judgment).

The judge also expressed similar criticism of another expert for the defence, stating that, whilst it is open to an expert to disbelieve or doubt a party in a dispute, this opinion must never undermine their duty under CPR 35 and the relevant practice direction, “either intentionally or recklessly”.


The Palmer case emphasises how essential it is for expert witnesses to appreciate their CPR 35 duty, which lies first and foremost to the court. Instructing solicitors should ensure that their experts are well trained in all aspects of their duty and its practical application.

To avoid the same criticism in this case, experts (and their instructing solicitors) are well advised to ensure that their opinion remains objective and unbiased at all times, and to be well aware of the tone of the language they use in their reports, specifically ensuring that it refrains from suggesting any level of unconscious bias. In addition, they should consider all material facts in a case, including those that are unfavourable to their instructing party – without placing unnecessary and questionable reliance on minor, or irrelevant evidence.

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