The UK Supreme Court has abolished the immunity expert witnesses have enjoyed for over 400 years. In Jones v Kaney [2011] UKSC 13 the court held, by a majority of 5 to 2, that there is no justification for granting expert witnesses immunity from suit in relation to their participation in legal proceedings.

Accordingly, the court held that an expert witness who does not act with reasonable skill and care should be held accountable.

This decision has obvious implications for surveyors who commonly act as expert witnesses in litigation, as it extends both to reports prepared in contemplation of legal proceedings and views expressed in court.

Key points:

  • Expert witnesses no longer have immunity from suit for professional negligence claims arising from their views or evidence in relation to legal proceedings.
  • Such claims may be brought in respect of breaches of duty that took place before the decision was handed down, subject to any limitation defence.
  • In practice, successful negligence claims against expert witnesses are likely to be rare. In light of the expert's overriding duty to assist the court, an expert will not be liable merely because he expresses a view which is unhelpful to the client's case.
  • All witnesses, including expert witnesses, will continue to enjoy an absolute privilege against claims in defamation arising from their evidence.

Practical implications:

  • Professional indemnity insurance premiums for expert witnesses may increase as a result of the abolition of the immunity, and this may result in an increase in fees charged by expert witnesses.
  • The decision may result in an increased focus on clauses to limit or exclude liability in an expert's terms of engagement.
  • It remains to be seen whether the decision will (contrary to the Supreme Court's view) have a "chilling" effect on the willingness of professionals to act as expert witnesses in litigation.


Mrs Kaney was instructed to act as expert in a personal injury claim brought by the claimant. Although her initial report was favourable to her client's case, she produced a subsequent report which altered her earlier position. The experts were ordered by a district judge to produce a joint statement and, after a telephone discussion between the two, a joint statement was prepared by the defendant's expert and signed by Mrs Kaney. It contained two extracts that were very damaging to the claimant's case.

The claim was then settled for considerably less than would otherwise have been the case, and a negligence claim was brought against Mrs Kaney alleging that she had been poorly prepared for the joint conference, had signed the report despite it not reflecting what she claimed she had agreed during the conference, and had forgotten key aspects of the case.

The case came before the High Court in January 2010 on a summary judgment application by Mrs Kaney to strike out the claim on the ground of expert witness immunity. Blake J felt bound by Court of Appeal authority (Stanton v Callaghan [1998] QB 75) to hold that an expert witness enjoyed immunity from suit, but granted a certificate to allow any appeal to leapfrog straight to the Supreme Court. The Supreme Court heard the claimant's appeal in January 2011.

Supreme Court decision

In the view of the majority (led by Lord Phillips), the starting point is that every wrong should have a remedy and any exception to this rule must be justified as being necessary in the public interest and should be kept under review. Accordingly, although expert immunity was long-established, the onus was on the expert to justify the immunity behind which she sought to shelter.

The majority concluded that there are no longer any policy reasons for retaining the immunity of expert witnesses from liability to their clients for breach of duty in negligence or contract. The majority considered, and dismissed, a number of arguments for upholding the immunity including:

  • Removing the immunity would discourage experts from providing their services

The majority could see no justification for this assertion. Other professionals who provide services which involve a duty of care are at risk of being sued. These professionals continue to provide these services, seeking insurance as necessary. There is no evidence that the appetite of barristers to take on instructions has diminished following the abolition of their immunity by the House of Lords in Hall v Simons [2002] 1 AC 615.

  • The immunity is necessary to ensure that expert witnesses give full and frank evidence to the court.

A concern was raised that a potential liability for negligence may render the expert less willing to express views contrary to his client's interests, either at a joint meeting or in court, or to change his view after discussions with the other party's witness. The majority did not accept this argument. Indeed it was felt that the most likely effect of potential liability on the part of the expert would be greater caution in preparing the initial report on the client's case (which was generally to be encouraged), rather than to inhibit frankness at a later stage.

  • Immunity protects experts from vexatious claims

The majority doubted that removal of the immunity would lead to a proliferation of vexatious negligence suits against experts, pointing out that barristers had not experienced a flood of such claims since their immunity was abolished. Moreover, a successful claim against a negligent expert would be rare given the need for the support of another expert.

Having considered these factors, the majority of the Supreme Court was not satisfied that there is sufficient justification to allow an expert witness to continue to benefit from immunity from a claim that he performed his services negligently. However, that did not affect the long-standing immunity enjoyed by witnesses of fact, nor the immunity of expert witnesses insofar as it relates to defamation claims arising out of their evidence.

Lord Hope and Lady Hale, who delivered dissenting judgments, viewed the issue from the opposite perspective. In their view, witness immunity is a long-established principle such that any exception to it, and not the rule itself, should be justified. Neither could see sufficient basis for removing the immunity in relation to claims for negligence against experts. If any change was to be made, it was more appropriately a matter for Parliament than the court.


In reaching its decision to abolish immunity from suit for expert witnesses, the majority of the Supreme Court was clearly influenced by the fact that advocates no longer enjoy immunity from suit following the House of Lords decision in Hall v Simons.

The majority considered the position of an expert witness to be much closer to that of an advocate than a witness of fact. Like the advocate, the expert witness owes a duty to exercise reasonable skill and care in providing services to the client. The majority emphasised that this duty includes, and does not conflict with, the overriding duty to assist the court, which may require the expert (or advocate) to act in a way which does not advance the client's case.

The majority of the Supreme Court has expressed confidence that experts will not be dissuaded from providing their services as a result of their new exposure to professional negligence claims. Whether that is the case remains to be seen. It is of course true that the abolition of immunity for advocates does not appear to have resulted in any shortage of advocates prepared to pursue claims on behalf of clients, and even before this judgment experts had no immunity against disciplinary proceedings (as a result of Meadow v General Medical Council [2007] QB 462) or wasted costs orders (Phillips v Symes (No 2) [2004] EWHC 2330) or civil suits in respect of their advice as to the merits of a party's claim (Palmer v Durnford Ford [1992] QB 483).

Further, the majority took pains to point out that it will not generally be straightforward to establish negligence against an expert witness.

Implications for the real estate sector

Real estate professionals such as surveyors who undertake expert witness work in matters such as lease renewals, rent reviews, dilapidations and wider-ranging valuations will take a particular interest in this case. It highlights the importance of acting with reasonable skill and care in the preparation of an expert report as well as in discussions with the other party's expert which may lead to an expert forming a revised view of his client's case. This is so particularly so given that an expert's opinion (for example as to rental values) can heavily influence a client's decision to settle. Should a client claim in negligence against an expert, damages for the different in rental value over a 25 year lease term could be substantial.

As pointed out by Lord Dyson, however, "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." The case therefore demonstrates the importance of providing sufficient market evidence and comparables to support the view put forward by an expert, as well as justification for the conclusions reached (and justification for any subsequent change of position). Such evidence will assist an expert facing allegations of negligence to demonstrate that he or she was acting entirely properly in reaching the view that he or she did.

Although clearly of wider application, this case specifically concerned the potential dangers associated with joint reports which are encouraged under CPR 35. If a joint report is ordered by the court, an expert will need to consult fully with his client and his client's legal representatives to ensure that he is wholly familiar with the view adopted by his opposite number before being satisfied that the joint report fully and fairly summarises his view before signing it.