This recent High Court case goes further than any other case on this subject – highlighting a specific duty on experts to disclose previous criticisms.
Table of contents
- Introduction
- Do experts have a duty to disclose previous criticisms of their evidence?
- What is the consequence of an expert failing to disclose previous criticisms of their evidence?
- Will an expert’s disclosure of criticism in a previous case impact the credibility of their evidence in subsequent cases?
- What can expert witnesses learn from this case?
1. Introduction
SC Commercial Bank Privatbank v Kolomoisky & Ors [2025] EWHC 1987 (Ch) is a case about a claimant bank’s allegation of misappropriation of funds.
In his judgment, Mr Justice Trower considered criticisms made of both parties’ experts. In relation to an expert instructed by the claimant, the judge himself had voiced criticisms in a previous, unrelated case. In relation to one of the defendants’ experts, despite judicial criticism in several earlier cases, this was not disclosed until three days before he was cross-examined.
However, he reached different conclusions for both experts.
2. Do experts have a duty to disclose previous criticisms of their evidence?
Judge Trower stated that there was a particular aspect of one of the defendants’ expert’s evidence that caused him “real concern as to the seriousness with which he had undertaken his overriding duty to the court.”
In two previous cases this expert’s evidence had been declared unreliable and therefore had not been accepted by the Commercial Court. In fact, in one case he had been specifically told by the judge that he should have disclosed criticisms of his evidence in two previous judgments.
However, despite this warning, it was only six months later, “a mere three days before his cross-examination in these proceedings, that the defendant’s solicitors disclosed to the Bank’s solicitors what had been said.”
The Judge concluded that the onus was on him, the expert, to ensure that this information was made available to the other party and the court much earlier on in this case.
3. What is the consequence of an expert failing to disclose previous criticisms of their evidence?
Mr Justice Trowers stated that failure to disclose previous criticism amounted to a breach of an expert’s duty to the court.
Whilst he was clear that this breach does not in itself mean that an expert’s evidence should be disregarded completely, their evidence should be (as it was in this case) subject to a higher level of scrutiny.
4. Will an expert’s disclosure of criticism in a previous case impact the credibility of their evidence in subsequent cases?
Mr Justice Trowers referenced a previous case whereby he had criticised the quality of the evidence produced by the claimant’s expert. In this case the expert had failed to understand his role, instead crossing the line into advocacy.
However, the judge stated that his evidence in this case “was in marked contrast”, stating “while he was firm in the views that he expressed, he did not cross the line into advocacy and explained the concepts on which he relied with clarity. He was confident in his opinions, and justifiably so. My overall impression was not just that he knew what he was talking about, but also that he addressed the issues with which he had been asked to deal in a fair and balanced manner.”
5. What can expert witnesses learn from this case?
This case makes it clear that experts must disclose any previous judicial criticisms of their evidence to their instructing solicitors, as soon as possible. They should also ensure that this information is made available to all other parties and the court. Not doing so would be tantamount to a breach of their overriding duty to the court.
If experts are concerned that such disclosures might impact the credibility of their evidence in subsequent cases, they should be reassured by the judgment in this case – highlighting that redemption is possible.
The consequence of concealment is much worse. No doubt litigators are likely to source this information as part of their preparation for trial and use it to undermine an opposing expert’s evidence in cross-examination.
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