Three Ways Expert Witnesses Were Criticised in Recent High Court Cases and What to Learn From Them
Evidence from expert witnesses carries real weight in court, it can determine outcomes that have enormous consequences for people involved. This is why courts hold experts to a high standard and why these three recent judgements are a reminder that expertise alone is not always enough.
This year there have been three cases which resulted in judicial criticism of expert witnesses, each in their different ways, but the underlying issues are one that any expert should take seriously. We’ve broken down what happened and what this means in practice.
1, Failing to set out the limitations of your evidence
In Mew v General Dental Council [2026] EWHC 1116, the expert didn’t include the limitations of his data in his written report, thinking he could address the limitations when questioned in the court. The judge disagreed, stating “This belied a fundamental misunderstanding of the obligations upon a CPR compliant expert, as embodied in the part of the expert’s statement of truth”
PD35.3.2(8) states ” if the expert is not able to give an opinion without qualification, state the qualification;”.
What this means for experts
Your report is your primary evidence and it must be complete, if your opinion comes with caveats, limitations or qualifications they must be in your report and not held back for the witness box. Transparency about the limits of your evidence is not a weakness.
What this means for instructing solicitors
When reviewing an expert’s report, check for these limitations, if they have caveated their opinion verbally but not in writing, ask them to address it. Choosing a service like ours means you have a dedicated client manager and all reports are 100% proof-read by our teams.
2, Applying the wrong standard of proof
In Alexander v HCA International Ltd & Anor [2026] EWHC 1284, the defendants experts were found to have been working to a scientific standard of certainty, a 95% confidence in a clinical negligence case.
HHJ Richard Roberts said “the standard of proof in a civil clinical negligence case is the balance of probabilities, namely more than 50%.”
“[The expert] is applying the standard required to submit a paper to a medical journal. In so doing, he fails to address the question to be answered by the Court of whether the Claimant would have avoided pancreatitis on the balance of probabilities.”
The same case also saw the judge criticise the defendants experts finding that his position is “untenable and would constitute substandard and negligent practice.” The expert stated in the report that he didn’t expect any discussion about the use of a particular drug to form part of the court’s consideration. HHJ Richard Roberts found that the experts “evidence on this point diminishes his credibility as an independent expert and results in my being able to place less weight on his evidence.”
What this means for experts
Going from clinical or academic work to an expert witness requires an intentional shift in how you frame your opinion. What is scientifically accurate in some cases doesn’t answer the courts questions on whether something is more likely than not. Experts must be prepared to answer that question clearly.
What this means for instructing solicitors
You should check with your expert, especially with those newer to medico-legal work that they understand the civil standard of proof and are framing their opinion against it.
3, Changing position under cross-examination
In Greening-Steer v Ainge [2026] EWHC 1239, a personal injury claim, the expert had video evidence showing the claimants mobility to be better than “anticipated” compared to the original assessment he had recorded. The expert made some adjustments to his opinion after seeing the footage, “but only slightly”
Then under cross-examination he changed his position substantially, conceding that the only explanation for the discrepancy was that the claimant had consciously exaggerated his symptoms. He then withdrew several key parts of his original report.
MR Justice Ritchie expressed that the expert “should have set out his true opinions on malingering in his last report, rather than waiting until cross examination to reveal them to the Court.”
What this means for experts
If new evidence causes you to reconsider your opinion, that must be reflected in your written evidence. Holding back a shift in your view until you are questioned in court exposes you to criticism and can undermine the value of your expert evidence.
What this means for instructing solicitors
If you become aware of new evidence that could affect your expert witness’s opinion make sure they have access to it promptly and ask for a written response. Don’t let changes in position emerge for the first time at trial.
These three cases involve different proceedings and different disciplines, however in each the expert failed to fully understand or fulfil their duty to the court.
Being a skilled clinician, psychologist, psychiatrist or specialist is the core of good expert witness work, but it’s not enough on its own. Understanding Part 35 of the Civil Procedure Rules, that govern the use of expert witnesses and evidence in civil court cases, knowing how to frame opinions against legal standards and keeping written evidence current when new information emerges are vital requirements of the role.
