IN Jones v. Kaney [2011] UKSC 13, [2011] 2 W.L.R. 823 the Supreme Court abolished expert witness immunity from suit, at least in some cases. The case itself concerned a party-appointed expert, and it is not clear whether the decision extends to single joint experts (see Lord Hope's remarks at [169] and [172]). This ambiguity, and others, leave expert witnesses in a state of uncertainty.

The proceedings resulted from a road traffic accident in which only damages were in dispute. The parties' expert witnesses came to different conclusions. The district judge ordered them to have a “discussion” and to make a joint “statement” under paragraph 35.12 of the Civil Procedure Rules. Jones's expert witness (Kaney) had originally reported that Jones was suffering post traumatic stress disorder, however the joint statement concluded that Jones had been “deceitful”. Jones's solicitors discovered from Kaney that the joint statement did not reflect what Kaney thought, but that she had felt under pressure to sign it. The district judge refused Jones's application for a new expert, and Jones was forced to settle his claim for significantly less than he might otherwise have expected to gain. Jones subsequently brought a claim against Kaney for compensation based on her alleged negligence. The first instance judge issued a “leapfrog certificate” under section 12 of the Administration of Justice Act 1969, enabling the case to proceed directly to the Supreme Court. The Supreme Court by a 5 to 2 majority, held that Kaney did not in fact have an immunity against civil liability.

A key difference between the majority and the minority was the presumption from which the Justices commenced their analysis. Whilst the Justices agreed that there was an immunity rule protecting experts who give evidence in civil proceedings, there was some disagreement as to whether there was a House of Lords precedent for this rule. Their conclusions on this point dictated the standard that the Justices used in their analysis. Those who believed that there was a precedent set a very high standard for revoking the rule, whereas those who did not placed the onus on the respondent to justify the rule. Lord Phillips (who gave the lead judgment for the majority) thought that “[i]t would not be right to start with a presumption that because the immunity exists it should be maintained unless it is shown to be unjustified”, and that the respondent had to “justify the immunity behind which she seeks to shelter” (at [51]). By contrast the dissenting judges (Lord Hope and Lady Hale), thought that any change must be justified as in the public interest, and any change must be sufficiently certain in scope. They concluded that there was insufficient justification. Thus whilst the majority concluded that the court should overturn the rule, the dissenters thought that reform should come from Parliament. The lack of certainty as to the history of the rule, the fact that only limited comparative analysis appears to have been offered, and the fact that the Justices do not appear to have had the benefit of third party submissions, suggest that Lord Hope and Lady Hale were right to prefer to leave the matter to Parliament.

What were the main arguments advanced by the majority? The majority dismissed as unconvincing the view that imposing liability might have a chilling effect on (a) whether expert witnesses would be willing to provide evidence, and (b) whether expert witnesses would be willing to give evidence contrary to their clients' interests. Instead they gave significant weight to the fact that abolishing immunity would bring expert witnesses into line with barristers (and other advocates), who no longer have any “court-room” immunity against civil liability. Indeed, it was suggested that the removal of advocates' immunity had not caused advocates to neglect their overridding duty to the court, and nor had this change precipitated a “flood of … claims from disappointed litigants” (at [59]). However, it is questionable whether this comparison is apt. Advocates have greater experience of court proceedings than experts; advocates will have undertaken professional training in the legal process; they will carry liability insurance; whereas some expert witnesses may rarely give evidence and will not necessarily have insurance. Furthermore, if the expert is a joint, single expert witness then a duty of care is presumably owed to both parties; but an advocate will not be in this curious position.

However, the biggest problem appears to be the lack of certainty surrounding the scope of the change. The appellant focused on “whether the act of preparing a joint witness statement is one in which an expert witness enjoys immunity from suit” (at [2]), but, as Lord Phillips noted, the submission “raised the broader issue of whether public policy justifies conferring on an expert witness any immunity from liability in negligence” (at [2]). Indeed whilst Lord Phillips's conclusion was limited to the abolition of immunity for “participation in legal proceedings” (at [62]), Lord Dyson concluded that any degree of immunity for expert witnesses could no longer be justified. Moreover, as Lady Hale and Lord Hope explained it is difficult to see how a principled line could be drawn so that immunity could operate in other proceedings or at other stages of the proceedings.

What are the likely consequences? No doubt some witnesses will seek insurance, which will increase the cost to the parties, although presumably they will not be able to insure retrospectively, and they may have difficulty identifying precisely what they need insurance for. Whilst the majority rejected “chilling effect” arguments, these arguments have found strong support from some academic commentators, and these points seem particularly compelling in the case of one-off expert witnesses. What impact did the Justices anticipate? Lord Brown (in the majority) thought that the most likely consequence would be “a sharpened awareness of the risks of pitching their initial views of the merits of their client's case too high or too inflexibly” (at [67]). However, whilst he welcomed this as a “healthy development” (at [67]), one might respectfully suggest that timid witnesses, hedging their bets, are undesirable. Such hesitant and defensive experts might drag out court proceedings and costs and make it far more difficult for the court and for the parties to assess the strength of their case.

Finally, one has to ask, was this necessary? Expert witnesses are not immune from disciplinary proceedings, nor from wasted cost orders. Of course these controls do not provide a remedy for the injured client. However, as Lord Brown noted, negligence on the part of expert witnesses is “no doubt rare” and “highly exceptional” (at [68]). In Jones v. Kaney the problem was brought to the judge's attention before the case was settled. Whilst one can see why the judge was reluctant to allow Jones to change his expert witness, would it not have been far simpler if the judge had ordered the experts to prepare a new joint statement, and issued a wasted costs order against Kaney for the expense of re-opening this aspect of the case?