Expert Witness in the Court Room: When Conduct Becomes Evidence: Lessons for Experts and Solicitors from Ellis & Ors v John Benson Ltd

An expert witness presents evidence in a courtroom, where the judge attentively listens from the bench.

Commentary by Professor Irfan Jeeva, Consultant Ophthalmologist and Expert Witness

The recent High Court decision in Ellis & Ors v John Benson Ltd [2025] EWHC 2096 (KB) provides an important reminder that witness behaviour is never incidental. It forms part of the evidential landscape that judges evaluate when assessing credibility, reliability, and ultimately the likelihood that a witness is telling the truth.

Bond Solon have commented on this judgment. Here, I offer my own perspective as an expert witness who works regularly across civil, family, and criminal jurisdictions.

1. The Courtroom Is a Test of Behaviour Under Pressure

In this case, the court was particularly concerned by the conduct of the defendant’s managing director when giving evidence. The judgment noted that his answers were at times aggressive, sarcastic, dismissive or openly belittling of counsel’s questions. These observations appear throughout the judge’s reasoning, including at paragraphs [50], [52], and [54].

The key point is not the individual comments, but what they revealed. A witness who becomes antagonistic during questioning risks demonstrating the very behavioural pattern that is at issue in the case.

For expert witnesses, this is an important reminder.

The courtroom does not simply test our knowledge.

It tests our composure, neutrality, and respect for the process.

2. Behaviour Can Influence Judicial Assessment

The judgment makes clear that demeanour during questioning may influence how the court assesses allegations about a witness’s conduct outside the courtroom. At paragraph [54], the judge observed that the behaviour displayed under formal questioning could inform how the witness may interact with others in a professional environment.

This is not an invitation to speculate on character. It is a recognition that conduct under cross-examination can legitimately assist the court in evaluating whether the concerns raised are consistent with observed behaviour.

For experts, this reinforces a fundamental truth:

Professionalism is part of the evidence.

3. Hostility and Sarcasm Undermine the Substance of Evidence

Even when a witness believes their underlying position is strong, an adversarial or dismissive tone can erode credibility. In this case, repeated comments dismissing counsel’s questions as “nonsense” or “ridiculous” (see para [50]) did not strengthen the witness’s stance. They weakened it.

Judges expect witnesses to:

• answer questions respectfully,

• demonstrate patience even under pressure,

• engage with the line of questioning rather than resist it emotionally.

Where the tone becomes combative, the judge may conclude that the witness is unwilling to be challenged, or unwilling to acknowledge the possibility of error.

For experts, this is critical. Independence must be reflected not only in the report, but in the manner of giving evidence.

4. Witness Familiarisation Is Not a Luxury. It Is Risk Management.

This case also illustrates the importance of ensuring that witnesses understand the realities of giving evidence. Cross examination can feel repetitive, uncomfortable, or confrontational. An unprepared witness may misinterpret the process as a personal attack and respond defensively.

Solicitors who invest in witness familiarisation reduce the risk of:

• reactive or combative responses,

• misinterpretation of questions,

• loss of judicial confidence,

• unnecessary damage to an otherwise defensible case.

For expert witnesses, familiarisation is equally valuable. It ensures that expertise is communicated clearly, calmly, and in a manner that supports the court’s task.

5. What Expert Witnesses Should Take From This Case

Drawing on my own experience, there are several important lessons for experts:

A. Behaviour is part of the evidence

Demeanour under questioning can support or undermine your credibility.

B. Neutrality must be visible

Even subtle sarcasm or frustration can appear partisan.

C. Patience is professionalism

The court expects clarity without confrontation.

D. Composure strengthens persuasion

Expert evidence is most persuasive when delivered with calm authority.

These principles apply across all jurisdictions, including civil negligence, safeguarding, Family Court, and criminal proceedings.

Conclusion

Ellis & Ors v John Benson Ltd offers more than a commentary on witness behaviour. It serves as a timely reminder that the quality of evidence is inseparable from the manner in which it is delivered. A witness who cannot maintain composure risks weakening their own position, no matter how strong their factual evidence may be.

For solicitors, the case reinforces the importance of witness selection and preparation. For experts, it reaffirms that our professionalism is evaluated alongside our expertise.

The courtroom is not simply a test of knowledge.

It is a test of conduct, clarity, and credibility.

Those who master all three best assist the court and maintain the trust placed in them as expert witnesses.