In our latest article, Christian Taylor, personal injury barrister at Exchange Chambers, considers recent criticism of expert witnesses and how to best keep the judge on your side when presenting evidence.

A gentle word of warning

Experts in personal injury litigation are used to writing reports, sometimes inappropriately favouring the party who instructs them, and expressing unrealistic or unsupported opinions, without ever being found out. Just occasionally, though, lightning strikes, and they are found out. This has happened twice in the last few months, with profoundly damaging results for the experts criticised by the judges in the cases I’ve summarised below.


It’s worth noting that most clinical negligence claims and serious personal injury claims resolve before trial. However, the small minority which resolve at trial are decided by judges who are often non-medically trained. In these cases, the issues for the judge to determine invariably involve them relying heavily upon the assistance of medical experts.

The task for the judge to decide which of the two very well-qualified medical experts to prefer is usually a difficult one. Such a decision is made much easier when the judge hears from an expert whom they consider to be very good or very bad.

Two recent judgments, one from Mr Justice Ritchie in Pickering v Cambridge University Hospitals NHS Foundation Trust [2022] EWHC 1171 (QB) and one from Judge Howells in Preater v Betsi Cadwaladr University Health Board [2022] (unreported), give some very helpful examples of good and bad practice.

Pickering v Cambridge

This claim concerned the failure of the defendant health trust to administer the anti-coagulant drug Heparin to the claimant, and whether her subsequent stroke would have been avoided. At the outset of the trial, the defendant denied breach of duty in failing to administer to the claimant low-molecular-weight Heparin by injection at accident and emergency (A&E).

The oral evidence of the defendant’s A&E expert on day one led the defendant to concede breach of duty at the conclusion of that day’s evidence. The defendant’s expert had focussed entirely on the leg clot and ignored the “mother” clot in her left atrium which had already “fired off” one embolus. He could not explain why it would be safe to make the claimant wait for anti-coagulation. In failing to deal with the issue of the “mother clot”, the defendant’s expert failed to deal with an issue that was of utmost relevance to the issues in the case.

During the course of the evidence by the claimant’s neurologist, he admitted that he had misquoted a paper in the joint report. His explanation for this had been that he was summarising a different paper, which he could not recall the name of and which he had not brought to court or produced to the defendant’s neurologist at the time of the joint report.

The defendant’s haematologist was criticised by Ritchie on the following grounds:

  1. Relying upon a chart in his oral evidence which he had not provided either to his instructing client, nor to the claimant’s expert, nor to the court, and which was not in the trial bundle nor referred to in his written evidence 
  2. For being “overly rigid” and “less than impressive” in failing to be persuaded by the logic of a leader in a particular field 
  3. Producing “rather extreme opinions” in defending his adopted position
  4. “Fixed thinking and questionable logic” undermined the credibility of his evidence. In this case, one of the issues where the judge found the expert’s logic questionable was in relation to him maintaining an argument that, notwithstanding, a blood clot would reduce in size once anti-coagulants were administered, the ability of the clot to “fire off” little pieces capable of causing strokes would be unaffected
  5. A reliance upon papers to prove something that “I consider they just do not prove”
  6. For refusing in his live evidence to go into details concerning why and how Heparin’s great success in abolishing the risk of emboli from blood clots in deep vein thrombosis and pulmonary embolism should be occurring so quickly, and why it is irrelevant to atrial clots.

Learning points

  • It is important to deal with all relevant issues in your evidence
  • Ensurethat any literature relied upon in support of a particular contention, does in fact support that contention
  • It’s vital that all material relevant to your opinion is included in your report
  • Make appropriate concessions or have very good reasons why you are not willing to do so.
  • Avoid expressing opinions that cannot be logically and evidentially justified
  • Any opinions must be capable of logical and evidential justification
  • Don’t rely upon literature to support something that it does not support
  • Answer questions in evidence and make appropriate concessions (unless you already have) and can articulate very good reasons for not doing so.

Panel members who are also members of the Expert Witness Institute (EWI) are able to read an interview on the private section of their website with the expert witness concerned, reflecting on their experience in this case.

Preater v Betsi Cadwaladr

This claim was for damages arising from the insertion of a vaginal mesh by the defendant, which the claimant said had caused her very significant pain and losses affecting all aspects of her life. The judgment returned 85/15 in her favour by consent. In relation to the significant elements of the claim, the defendant obtained surveillance and social media evidence, and argued that the claimant was exaggerating by lying about the effect of the medical procedure on her disability and losses.

Much of the judgment was taken up considering the lay witness evidence. As with the previous case outlined, there are some useful insights into what the judge found important about the experts’ evidence.

Howells’ key observations

  1. In relation to the defendant’s urologist, the judge concluded that he had not fully considered all the evidence. In particular, issues surrounding surveillance, along with the fact that the claimant had used a stick while attending court and he “appeared to be rather too willing to reach conclusions in support of the defendant’s position on only parts of the evidence”
  2. The claimant’s pain expert was praised for evidence that was “balanced and considered. He made realistic concessions and was unshaken in cross examination. He was an impressive witness”
  3. The defendant’s pain expert was also praised for his evidence as “very balanced and thoughtful. He made realistic concessions and impressed me that he was doing his utmost to present a fair opinion.” There was in fact significant agreement between the two pain experts
  4. The defendant’s gynaecologist was criticised for commenting and highlighting “inconsistencies, without giving the balance of recording consistent presentation as well. I did not find this to be an attractive approach from an expert witness.”
  5. Criticism was also levelled at the defendant’s psychiatrist for failing to include in her report that the claimant was seen limping on several occasions, and that she had impaired walking. Furthermore, the expert concluded that it was her error in stating that the claimant had been “unable to go out” and that this was not something that the claimant had disclosed. Judge Howells criticised her for “not preparing her report with sufficient care and…not providing a balanced view”
  6. In her general conclusions the judge concluded that “a number of the other experts appear to be straying way beyond their area of expertise”. For instance, there were occasions when an expert was prepared to comment upon the surveillance or social media evidence, so as to draw adverse conclusions, but ignored other parts of that same evidence which would not support the opposing conclusions drawn.

Learning points

  • An expert must be independent and impartial. One test for this is whether the expert would have provided the same opinion if they had been instructed by the other side
  • Make appropriate concessions. It’s important to express an opinion in which you are confident and can logically and evidentially justify
  • Take appropriate care when compiling reports.
  • If you decide it is within your remit to comment upon surveillance/social media, ensure you do so impartially, highlighting matters which both support and undermine your case. It’s vital not to “cherry-pick” the evidence.

Final thoughts

I realise that there is significant repetition in lessons that I have drawn from the judges’ conclusions. This is because experts across a variety of disciplines in just two cases failed to adhere to basic principles of impartiality and competence. Aside from the very public criticism of their professional opinions and lay clients who have suffered expensive losses at trial, this is likely to lead to courts’ thinking twice about trusting their opinions in the future.

Christian Taylor acts for people with clinical negligence and serious personal injury claims, practicing from Exchange Chambers. During his near 20 years in practice, he has read thousands of medical expert reports, participated in hundreds of conferences with such experts, and when needs must, has called and cross-examined expert witnesses at trial.

Christian has acted on behalf of hundreds of successful claimants and helped recover millions of pounds in compensation on their behalf. The highest value claim in which he was involved as junior counsel was just under £10 million.

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