The Supreme Court has today handed down a landmark judgment in Paul Wynne Jones v Sue Kaney [2011] UKSC 13 abolishing blanket immunity enjoyed by expert witnesses.

This decision will have serious implications for Insurers operating in the professional indemnity market given the growing trend of professionals undertaking expert work.


The general rule of law is that every wrong should have a remedy and that any exception to this rule must be justified as necessary in the public interest. Witness immunity dates back over 400 years and is considered to constitute such an exception.

Historically, immunity covered witnesses of fact, barristers and expert witnesses. The rationale for immunity enjoyed by expert witnesses arises from the well-established principle of law that witnesses giving evidence in good faith should be protected from liability arising from their testimony. As a result, experts have, until now, been accorded blanket immunity to allow them to give their evidence “fearlessly”. The courts took the view that public interest in ensuring experts are not deterred from testifying transcended the need to provide a remedy to individuals.

However, the justification for blanket immunity was undermined by the House of Lords in Arthur JS Hall v Simons [2002] 1AC 615, which swept away barristers’ immunity. Since then, the only body of professionals to enjoy blanket immunity has been the expert witness fraternity.

With the Supreme Court decision in Jones v Kaney, blanket immunity no longer applies to experts.

The Facts

Mr Jones sought damages for personal injury following a road traffic accident. Dr Kaney was retained as an expert to advise on the psychological aspects of the psychiatric injury claim. After conferring with the opposing expert, Dr Kaney signed a joint statement agreeing that Mr Jones was being “deceptive and deceitful” in portraying his symptoms.

The claim settled at a significant undervalue and Mr Jones issued negligence proceedings against Dr Kaney. However, Dr Kaney pleaded expert immunity and applied to have the claim struck out.

Mr Justice Blake was bound by previous authorities on expert immunity to strike out the claim. Nevertheless, since the case involved a point of law of public importance, he granted a “leapfrog certificate” to allow the Supreme Court to consider the issue. In doing so he stated:

“…a policy of blanket immunity for all witnesses, indiscriminately protecting witnesses as to fact and…expert witnesses….may well prove to be too broad to be sustainable and therefore disproportionate. The public benefit of truthful, accurate, reliable and frank evidence to the court is unlikely to need such broad immunity.”

The Supreme Court Judgment

This morning, the Supreme Court echoed Mr Justice Blake’s concerns and abolished expert immunity with a majority of five to two, citing a number of reasons to include the following:

  • There is no conflict and should be no conflict between the duty owed by an expert to his client to provide a service with reasonable skill and care and the duty he owes to the court. The Supreme Court found that there was no “divided loyalty”.
  • The primary rationale for retaining immunity was a concern that expert witnesses may be reluctant to give evidence contrary to their clients’ interests and in breach of duties to the court if there was a risk this might lead clients to sue. The Supreme Court held that there was no reason to believe that the presence of immunity was fundamental to ensuring an adequate supply of professionals willing to act as experts. This was an argument used before the court in addressing barristers’ immunity and there is no short supply of advocates.

Lord Phillips, who gave the lead judgment, summarised the majority view as follows:

“There are no longer any policy reasons for retaining immunity from suit for professional negligence by expert witnesses… The practical reality is that, if the removal of immunity would have any effect at all on the process of preparation and presentation of expert evidence (which is not likely in any event) it would tend to ensure a greater degree of care…” on the part of the expert.

Impact on the Professional Indemnity Market

Whilst the existence of professional indemnity insurance for experts was not referred to as a factor in the decision reached by the Supreme Court, the judgment does comment on this issue. The clear implication of this decision is that Insurers will need to consider carefully the risks they now undertake in writing policies for professionals acting as experts.