Summary and relevance  

Until now, expert witnesses who gave evidence in court could not be sued for giving evidence negligently or for the negligent content of a report on which their evidence is based. However, in Jones v Kaney, the Supreme Court has ended that protection which has existed for the last 400 years.  

The case related to a Personal Injury matter, but is highly relevant to the resolution of construction disputes, which rely upon complex technical evidence, often from a number of experts.  

The case has implications for expert witnesses themselves and those appointing them, because the availability of highly qualified experts who are willing and able to give evidence in relation to construction disputes is key to their successful resolution.

Immunity previously enjoyed by expert witnesses

It has long been the position, dating back over 400 years, that an expert witness who gives evidence in court cannot face a claim in relation to anything he says in court.

The protection was extended by the case of Palmer v Durnford Ford to cover reports and work which was preliminary to giving evidence in court, but it was made clear that reports or work done for the purpose of advising a client was not covered.

A further extension was given by the Court of Appeal in Stanton v Callaghan to cover joint meetings between opposing experts in the early stages of litigation.

Origins and rationale for the special treatment of expert witnesses

The protection originally provided to expert witnesses arose from a concern that without it, expert witnesses would be reluctant to provide their services and that reluctance might extend to not giving evidence that was contrary to their client’s interest for fear that a client unhappy with the outcome of the court hearing or settlement might sue them.

This would cut across an expert’s duty to the court to give full and frank evidence.  

The rationale for the extension in Palmer v Durnford Ford was to avoid the situation where the protection was circumvented by bringing a claim solely on the underlying report.

Stanton v Callaghan provided a further extension to promote the experts’ ability to make concessions during the joint meetings, which may well mean a departure from reports previously prepared. This is just the purpose of joint expert meetings.

Jones v Kaney

The case involved a claim by a client against an expert who agreed a joint statement with the opposing expert that differed from previous reports in a way which was detrimental to the client’s case.  

The Supreme Court considered the question of experts’ immunity to be an issue of such public importance that it looked at the entire issue of expert immunity afresh and decided to abolish the protection completely (except for defamation).  

Divided Loyalty?

Expert witnesses can owe duties to their client, and simultaneous owe an overriding duty to the court. This seeming conflict of loyalties and the risk that an unhappy litigant might sue was long held as justification for the immunity which benefits expert witnesses.  

The majority in the Supreme Court however saw no conflict or threat and stated that “if the expert gives an independent and unbiased opinion which is within the range of reasonable expert opinions, he will have discharged his duty both to the court and his client”. However, if the expert gives “an independent and unbiased opinion which is outside the range of reasonable expert opinions”, he “will be in breach of the duty owed to his client”.  

Are expert witnesses reluctant to act for fear of being sued by unhappy clients?

A majority in the Supreme Court were not convinced by a survey of expert witnesses taken at the 2010 annual Bond Solon expert witness conference which found that the removal of the immunity would deter expert witnesses from offering their services. The Court was also not convinced that removal of the immunity would prevent expert witnesses from providing full and frank evidence to the court.  

Only time will tell whether experts will in fact be reluctant to act.

Jones v Kaney  

Stanton v Callaghan  

Palmer v Durnford Ford

[1992] QB 483 (hyperlink unavailable)