Expert evidence - Expert witnesses - Immunity from suit - Justification

Paul Wynne Jones v Sue Kaney: SC (Justices of the Supreme Court: Lords Phillips (president), Hope (deputy president), Brown, Collins, Kerr, Dyson, Lady Hale): 30 March 2011

The appellant (J) appealed against a decision ([2010] EWHC 61 (QB), [2010] 2 All ER 649) striking out his claim for negligence against the respondent psychologist (K).

K had been instructed to prepare an expert report in relation to a claim by J for damages sustained in a road traffic accident.

K’s initial report suggested a diagnosis of post-traumatic stress disorder.

An expert appointed for the defence concluded that J was exaggerating his symptoms and, as a result, a joint statement was ordered. The joint statement was very damaging to J’s case.

It transpired that K had signed the joint statement without any comment or amendment.

As a result the matter settled for a much smaller sum. J issued proceedings for negligence and K’s defence was a plea of witness immunity in accordance with the decision in Stanton v Callaghan [2000] QB 75 CA (Civ Div). J’s case was struck out on the basis that Stanton was binding upon the court.

The issue on appeal was whether public policy continued to justify conferring on an expert witness immunity from liability in negligence in relation to the performance of his duties in that capacity.

Held: (Lord Hope and Lady Hale dissenting) (1) The primary case for conferring immunity from liability in negligence on expert witnesses was the ‘chilling effect’ that the risk of claims arising out of conduct in legal proceedings would have.

That was the reluctance of an expert witness to provide his services at all and to give evidence that was contrary to his client's interest if there was a risk that might lead his client to sue him (see paragraph 41 of judgment).

(2) If the immunity was to be effective in removing inhibitions on what an expert witness was prepared to say at trial, its scope must extend to protect him in relation to his expression of views before the trial, Palmer v Durnford Ford [1992] QB 483 QBD considered (paragraph 43).

(3) It was common ground that if immunity was to be effective it must apply to views expressed not only in court, but in contemplation of, or at least preparation for, possible proceedings.

The vast proportion of claims settled before getting to court and thus the effect of the immunity was to preclude the client from suing for breach of duty where the expert’s negligence was alleged to have adversely affected such a decision to settle (paragraph 45).

(4) The case of Arthur JS Hall & Co v Simons [2002] 1 AC 615 HL had swept away an advocate’s immunity from liability in negligence, in court and out, without questioning the immunity of expert witnesses.

The court had distinguished expert witnesses on the ground that they owed no duty to their client once they were in the witness box; their sole duty was then to the court.

That distinction was wrong. There was no longer any scope for contrasting the duty owed by an expert to his client with a different duty to the court. There was no conflict between those duties.

The expert witness had that in common with the advocate, Hall considered (paragraphs 46-50).

(5) It would not be right to start with a presumption that because immunity existed, it should be maintained unless it could be shown to be unjustified.

The onus lay on K to justify the immunity behind which she sought to shelter.

There was no justification for the assumption that if expert witnesses were liable to be sued for breach of duty they would be discouraged from providing services at all.

All who provided professional services which involved a duty of care were at risk of being sued for that breach of duty. They customarily insured against that risk (paragraph 54).

Further, the justification that immunity was necessary to ensure the expert performed his duty to the court, and gave his honest opinion even if that proved adverse to his client’s case, was not made out.

A witness of integrity faced with having to change his view would do so. A lesson could be learned from the position of advocates.

Removal of their immunity had not resulted in any diminution of their readiness to perform their duty to the court.

(6) It followed that the immunity from suit for breach of duty that expert witnesses had enjoyed in relation to their participation in legal proceedings should be abolished, Stanton overruled.

That conclusion did not extend to the absolute privilege that they enjoyed in respect of claims for defamation.

(7) (Per Lord Hope and Lady Hale) The question in the case was whether the reasons which justified immunity for witnesses generally, did not apply to expert witnesses.

The grounds for making that exception by judicial decision to the long-established rule had to be examined very carefully, as an incautious removal of the immunity from one class of witness might destabilise the protection given to witnesses generally.

The lack of a secure principled basis for removing the immunity from expert witnesses, of a clear dividing line between what was to be affected by the removal and what was not, and of reliable evidence to indicate what the effects might be, suggested that the wiser course would be to leave any reform of the law to parliament.

Appeal allowed.

Roger Ter Haar QC, Daniel Shapiro (instructed by Hill Dickinson) for the appellant; Patrick Lawrence QC, Charles Phipps (instructed by Berrymans Lace Mawer) for the respondent.