Professionals risk losing their immunity as experts.

Generally speaking, professionals are held accountable for their actions. One major exception though is when they act as expert witnesses. For public policy reasons, such witnesses enjoy immunity from both civil and criminal legal action. But this principle is about to be reviewed by the UK Supreme Court and may well be abolished altogether. If this happens, there will be serious implications for insurers operating in the professional indemnity market.

It is a well-established principle of law that witnesses giving evidence in good faith should be protected from liability arising from their testimony. This principle has been extended by the courts to professionals who act as expert witnesses. They are accorded blanket immunity, it is said, so that they will be able to give their evidence fearlessly.

However, expert immunity has come under scrutiny in recent years and the case of Paul Wynne Jones v Sue Kaney [2010] EWHC 61 (QB) is set to challenge the principle.

Reasons for immunity

The leading authority for expert immunity is the Court of Appeal decision in Stanton v Callaghan [2000] QB 75. In a claim against insurers, the Stantons relied on the evidence of an expert witness – a Mr Callaghan – who subsequently revised his views, thereby undermining the claim. The Stantons sued but the Court of Appeal upheld Mr Callaghan’s claim to immunity.

The court held that there was no justification for distinguishing between an expert and a lay witness. Just like other witnesses, experts are covered by the general policy established in Saif Ali v Sidney Mitchell and Co [1980] AC 198 that trials should be conducted “without avoidable strains, intentions of alarm and fear in those who have a part to play in them”. The public interest in ensuring experts are not deterred from testifying transcends the need to provide a remedy for individuals.

However, even in Stanton, doubts about the principle of blanket immunity were evident, with Lord Justice Chadwick saying that “the proposition that the defendants can escape liability for negligence on the ground that [advice] was given in the context of litigation requires careful scrutiny”.

End of barristers’ immunity

The justification for blanket immunity was undermined by the House of Lords in Arthur JS Hall v Simons [2002] 1AC 615, which reviewed barristers’ immunity. The House of Lords ruled that the public policy arguments for immunity were no longer appropriate for barristers and the immunity was therefore lifted. This decision is likely to have a significant impact on the court’s review of expert immunity.

There were several reasons for the law lords’ decision in Hall, including the fact that courts now had power under the Civil Procedure Rules to prevent an abuse of process. In addition, it was said that a court could distinguish between true negligence of barristers and the sorts of errors of judgment that are inevitable when practising the art of advocacy. Consequently, there would not be a sudden flood of negligence claims against barristers.

The issue ultimately came down to the key distinction between barristers and lay witnesses: barristers owe a duty of care to their client, whereas lay witnesses owe no duty except to tell the truth.

Is a change in the law overdue?

The change in the law relating to barristers’ liability has shifted the focus onto expert immunity and arguments used in Hall may well be applied to the Paul Wynne Jones case to finally determine this tricky area of the law.

The court may find that the principles applied to barristers in lifting barristers’ immunity also apply to experts.

In the latter case, Mr Jones sought damages for personal injuries 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. It later emerged that Dr Kaney had felt pressured into agreeing with the opposing expert.

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

Mr Jones argued that expert immunity under Stanton is no longer binding because that case:

  1. was based on the principle of barristers immunity, which has now been lifted; and
  2. it preceded the Human Rights Act, the application of the right to a fair trial under Article 6 of the European Convention on Human Rights and case law indicating that blanket immunities may be contrary to Article 6.  

The district judge at the first hearing and Mr Justice Blake in the High Court both took the view that they were bound by Stanton. However, Mr Justice Blake hinted that the courts are ready to lift expert immunity, saying “there is substantial likelihood that on re-examination by a superior court…it will emerge that the public policy justification for the rule [on expert immunity] cannot support it”.

Given the significant public interest and legal issues involved, the claimant has been granted what is known as a “leapfrog” certificate, asking the Supreme Court for permission to appeal. The case goes before the Supreme Court in January 2011. For professionals who act as expert witnesses – and for their insurers – this is a case to watch.


There are, of course, good public policy reasons for ensuring that expert witnesses are able to give their evidence freely. However, there is now a feeling that the law needs to be changed because all professionals should be held accountable and because blanket immunity is seen as an expanding area of legal injustice. Since the removal of barristers’ immunity, there has been a growing expectation that expert immunity will also be abolished before too long.  

Given this climate, the Supreme Court is likely to seize the opportunity of carrying out an in-depth review of this area of the law. Right now, therefore, the survival of expert immunity is hanging in the balance. But if the Court does rewrite the immunity rules, this will have a significant impact on the professional indemnity market, as more and more professionals take on expert work to supplement their core business.