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Expert Witness Immunity Removed: Jones v Kaney

03 May 2011

In this article, Beverley Vara looks at the case of Jones v Kaney in which the Supreme Court has overturned 400 years of practice and has held that a party can sue its own expert witness for negligence in the litigation.


Mr Jones was claiming for the psychological after effects of a road accident and instructed Dr Kaney as his expert. Her report was positive. The court ordered her and the other side’s expert to agree a joint report. The joint report was much less favourable to Mr Jones and he had to settle his claim at a lower amount than he had been expecting. Dr Kaney had signed the joint report despite not having seen the other expert’s own report and feeling that the joint report did not reflect her views. Mr Jones sought to sue her for negligence. Dr Kaney relied on the centuries-old policy of protecting expert witnesses from being sued.

The Supreme Court did not find that the traditional justifications – experts’ fear of being sued making them unwilling to act and the risk of vexatious litigation trying to rehash the original trial – were convincing. Experts can be sued by their clients for negligence for non-contentious work and that risk does not put experts off acting. The courts themselves would see off unmeritorious claims against experts. Like advocates, whose own immunity from suit was removed by a House of Lords’ decision some years ago, experts could be liable if they were negligent in litigation. Experts, of course, have an overriding duty to the court, which may require them to act in a way which is adverse to their own client’s interests, but a change of mind for a good reason is not negligent.

The consequences

The majority in the Supreme Court were confident that they were not opening the gates to a flood of speculative cases by disgruntled litigants, largely on the basis that there has been no such flood since barristers’ immunity was removed. The dissenting judges felt there was no evidence about the likely consequences and that such a significant change should be left to Parliament. In these days of straitened Legal Aid and new curbs on recovery under contingent fee arrangements, it is certainly difficult to see where the funding for many challenges would come from, but there are always those with deep pockets and those acting as litigants in person who may not be discouraged from trying to refight their battles by attacking their experts.

The risk for experts is that their overriding duty to the court may cause a legitimate change of mind. The client may find it hard to accept that the expert he has paid has a duty which overrides that owed to him. The decision only applies to client/own expert action; there is no suggestion that a party could sue the other side’s expert for his evidence.

Stanton v Callaghan

Before this case, the leading decision involved a structural engineer who revised his view about the type (and cost) of necessary repairs for subsidence in a house. He was sued for his change of mind. The Court of Appeal felt that experts should be free to change their mind without fear of being sued and that immunity was necessary for that. If the same case was heard today, following the Supreme Court decision, the structural engineer would not be immune from action, although it is clear from the Supreme Court’s comments that a change of mind does not of itself justify an allegation of negligence.

For experts the case does create new risks. The careful expert may face further litigation but this, of course, would prove hopeless since the expert would win. The careless expert deserves little sympathy. For both, it will be important to make sure that their professional indemnity insurance provides adequate cover for the new liability.

What does not change

All witnesses – expert and lay – and all those involved in the proceedings – judge, advocates and jury – are protected from defamation claims about what they say in court. Lay witnesses also continue to be immune from action for their evidence. Unlike experts and advocates, they are usually not there willingly and might well be put off if they feared further legal action because they wavered in their evidence of fact or did not stand up well to cross examination. Of course, all witnesses remain liable if they perjure themselves.

Experts may also be liable to their professional bodies where these exercise a ‘fitness to practise’ jurisdiction.

Source: Jones v Kaney [2011] UKSC 13, Stanton v Callaghan [1998] 4 All ER 961