UK: UK Supreme Court abolishes 400 year rule

Last Updated: 24 May 2011
Article by Denis Brock and Edmund Wan

On considering an appeal from the High Court of Justice, by a majority of five to two, The Supreme Court recently overturned the 400 year old rule that an expert witness enjoyed immunity from any form of civil action arising from the evidence that he or she gave in the course of proceedings.

The facts

The issue, which arose in the recent case of Jones v Kaney was whether the act of preparing a joint witness statement is one in respect of which an expert witness enjoys immunity from suit. The issue arose out of a personal injuries action in which the appellant, Paul Jones, had been claiming damages for physical and psychiatric consequences arising from an accident in which he had been hit by a car.

Mr Jones suffered physical injuries, but more significantly he suffered post traumatic stress disorder (PTSD), depression, an adjustment disorder and associated illness behaviour which manifested itself in chronic pain syndrome. As a result, a clinical psychologist, Dr Sue Kaney, was instructed on behalf of Mr Jones to act as an expert witness.

Prior to the issue of proceedings, Dr Kaney prepared a report dated 29 July 2003, in which she expressed the view, inter alia, that Mr Jones was at that time suffering from PTSD. Proceedings were then issued. Liability was admitted soon after leaving only damages at issue.

Upon instructions from Mr Jones' solicitors, Dr Kaney carried out a further examination of Mr Jones and issued a second report dated 10 December 2004. This stated that Mr Jones did not have all the symptoms to warrant a diagnosis of PTSD, but was still suffering from depression and some of the symptoms of PTSD. A subsequent report prepared by Dr El-Assra, a consultant psychiatrist instructed by the defendant's insurers, expressed the view that Mr Jones was exaggerating his physical symptoms. The district judge then ordered the two experts to hold discussions and to prepare a joint statement. The discussion took place on the telephone and a joint statement was duly prepared.

The joint statement recorded agreement that Mr Jones' psychological reaction to the accident was no more than an adjustment reaction and did not reach the level of a depressive disorder of PTSD. It further stated that Dr Kaney found Mr Jones to be deceptive and deceitful in his reporting and that the experts agreed that his behaviour was suggestive of 'conscious mechanisms' that raised doubts as to whether his reporting was genuine.

When asked by Mr Jones' solicitors to explain the discrepancy between the two reports, Dr Kaney explained:

  • that she had not seen the reports of the opposing expert at the time of the telephone conference
  • the joint statement, as drafted by the opposing expert, did not reflect what she had agreed in the telephone conversation, but she felt under some pressure in agreeing to it
  • her true view was that Mr Jones had been evasive rather than deceptive
  • it was her view that Mr Jones did suffer PTSG which was now resolved
  • she was happy for Mr Jones's solicitors to amend the joint statement.

Mr Jones' solicitors sought to change their client's expert witness, but the district judge would not permit this. As a consequence, Mr Jones' solicitors felt constrained to settle the claim for significantly less than they would have achieved had Dr Kaney not signed the joint statement.

Pre-judgment state of the law

Immunity of expert witnesses dates back over 400 years , long before the development of the modern law of negligence and, in particular, the recognition of the possibility of liability for negligent misstatement. It also well pre-dates when it became common to call experts to give evidence in proceedings.

It has been described as a matter of public interest that those who take part in a trial ie. judge, jury and witnesses, are given civil immunity for their participation. The primary rationale for the immunity was a concern that an expert witness might be reluctant to give evidence contrary to his client's interest, in breach of his duty to the court, if there was a risk that his might lead his client to sue him. Pertinently, in the 2000 case of Stanton v Callaghan the Court of Appeal held that the immunity of an expert witness extended to protect him from liability for negligence in preparing a joint statement for use in legal proceedings.

Comparison with immunity for advocates

The majority likened the immunity enjoyed by expert witnesses to that enjoyed by barristers prior to its abolition by the House of Lords in 2001 on the ground that it could not longer be justified. It was found that in common with advocates, there was no conflict between the duty that the expert had to provide services to his client with reasonable skill and care, and the duty he owed to the court. The evidence did not suggest that the immunity was necessary to secure an adequate supply of expert witnesses and the removal immunity for advocates had not diminished their readiness to perform their duty, not had there been a proliferation of vexatious claims or multiplicity of actions.

Immunities which remain unaffected by the decision

The decision does not affect an expert witness' absolute privilege from claims in defamation nor the immunity of other witnesses in respect of litigation.


Professionals who act in the capacity of expert witnesses should be aware of the change in the law and ensure that they understand and comply with their duties of due skill and care to the client and to the court. Litigants engaging expert witnesses should take care to engage a professional who has a good reputation in his or field and who is experienced in acting as an expert witness.

Whilst the decision in Jones v Kaney affords a remedy to litigants in circumstances where an expert has breached his duty of care to the client, litigation can be time consuming and expensive and therefore prevention is better than cure.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

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