A recent High Court case provides some important observations on whether an expert witness who has been given limited instructions is under a duty to refuse them. The judge concluded in the negative but did state that there could be “extreme” cases where an expert must decline instructions.
The facts of the case
Presbar Diecastings Ltd v GW Atkins & Sons Ltd & Anor [2026] EWHC 399 (Ch) is a trial of a claim and counterclaim arising out of an asset purchase agreement (APA) made between the claimant (a high-pressure aluminium diecasting business), the first defendant as purchaser and the second defendant as guarantor.
The claimant sued for the balance of the stated purchase price payable under the APA as the first defendant had only paid the first instalment and had not paid the remainder, which was due to be paid in the 24-month period after completion.
The expert evidence came from industry experts and accountancy experts. The defendant’s accountant was given limited terms in relation to the compiling of the expert report. He was subsequently subject to criticism by the claimant’s counsel.
Criticism of the defendant’s accountant
The defendant’s accountant was given “very specific instructions as to the approach he should take in relation to his valuation exercise, which he set out in detail in his report”.
He was subject to criticism by the claimant’s counsel in cross-examination and closing submissions who suggested that the expert “ought to have appreciated both that these instructions were inconsistent both with the conventional instructions to be given to an accountancy expert when valuing a breach of warranty claim and that they required him to undertake little more than an arithmetical exercise as opposed to an exercise of independent accountancy expertise and opinion”.
Did the judge consider this a fair criticism?
HHJ Stephen Davies did not perceive this to be a “fair criticism” of the defendant’s accountant.
Although the instructions he received were “certainly more limited than would be normal in a case such as this”, his “overriding duty to the court as an independent expert” did not extend to him:
- Declining to accept instructions in these circumstances.
- Proffering his opinion on wider valuation issues even in relation to issues outside of his instructions.
The judge commented that reputable solicitors had instructed the expert. Also, that he was completely transparent in his report and in his evidence about what he had been instructed to do and what he had done.
When might an expert be bound to refuse instructions?
The judge in this case indicated that there “may be extreme cases where an expert is bound to refuse instructions where, for example they require the expert to assume certain facts or certain propositions which are plainly untrue or inappropriate”.
Rule 27 of the Guidance for the instruction of experts in civil claims provides some direction as to when an expert might withdraw from a case: “Where experts’ instructions are incompatible with their duties, through incompleteness, a conflict between their duty to the court and their instructions, or for any other reason, the experts may consider withdrawing from the case.
“However, experts should not do so without first discussing the position with those who instruct them and considering whether it would be more appropriate to make a written request for directions from the court. If experts do withdraw, they must give formal written notice to those instructing them.”
What can experts learn from this case?
This case presents useful guidance to experts who find themselves on the receiving end of limited instructions.
It is notable that whilst the limitations imposed did cause the judge to give less weight to his report, the expert’s transparency in his report and his evidence were instrumental to the judge’s finding that he had acted properly.
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