In 2001 Mr Jones was seriously injured when a drunk and uninsured driver knocked him off his motorcycle when it was stationary.
The relevant insurer for the Motor Insurance Bureau accepted liability, three years later, so that only quantum remained in issue. Mr Jones’ solicitors instructed Dr Kaney, a consultant clinical psychologist, to report on the psychological aspects of Mr Jones’ injuries. The insurer’s expert thought that Mr Jones was exaggerating his symptoms. The two experts ‘met’ by telephone and the insurer’s prepared a draft joint statement which Dr Kaney signed without amendment or comment. The joint statement clearly damaged the appellant’s claim, for example, it raised doubts as to whether his subjective reporting was genuine.
When questioned on what she had done, Dr Kaney said that it did not reflect what she had agreed to on the telephone, but she felt under some pressure to agree to it; she was happy for the joint statement to be amended. However it was now too late: the district judge refused to permit the appellant to change experts and he had to settle the claim for significantly less than he would have otherwise received. Mr Jones sued Dr Kaney for negligence. Dr Kaney argued expert witness immunity from suit, relying on the Court of Appeal case of Stanton v Callaghan  QB 75. Mr Jones’ claim against Dr Kaney was struck out in the High Court. He “leapfrog” appealed directly to the Supreme Court on ‘a point of law of general public importance’ (section 12 of the Administration of Justice act 1969). The Supreme Court allowed the appeal and held that the immunity from suit for breach of duty that expert witnesses had enjoyed in relation to legal proceedings should be abolished.
The majority (5-2) was guided by the principle that ‘where there is a wrong there should be a remedy’. Lord Phillips for the majority attached considerable importance to the House of Lords decision in Hall v Simons  1 AC 615 which ‘swept away the advocate’s immunity from liability in negligence, in court and out, albeit not their absolute privilege from claims for defamation.’ (para 34). Comparing and contrasting advocates and expert witnesses in the context of immunity from suit, he said,
‘Each undertakes a duty to provide services to the client. In each case those services include a paramount duty to the court and the public, which may require the advocate or the witness to act in a way which does not advance the client’s case. The advocate must disclose to the court authorities that are unfavourable to his client. The expert witness must give his evidence honestly, even if this involves concessions that are contrary to his client’s interests. The expert witness has far more in common with the advocate than he does with the witness of fact.’ (para 50)
He went on to put expert witnesses in the same position as advocates:
‘I consider that immunity from suit for breach of duty that expert witnesses have enjoyed in relation to their participation in legal proceedings should be abolished. I emphasise that this conclusion does not extend to the absolute privilege that they enjoy in respect of claims in defamation.’ (para 62)
Things we know…
We know that this decision impacts upon expert witnesses in civil, family and criminal cases. Lord Dyson (at para 125) could ‘see no reason to treat expert witnesses who are engaged in criminal and family litigation any differently from those engaged in civil litigation’. Lord Phillips (at para 60) explained expert witnesses’ liability in criminal cases : ‘my conclusions hold good in the case of the duty owed by an expert witness to the client who retains him in a criminal trial. I concede, however, that the risk of vexatious claims from those convicted of criminal offences may be greater. Such claims will, however, be struck out as an abuse of process unless the convicted client first succeeds in getting his conviction overturned on appeal’. The abuse of process defence for criminal cases is exactly the same for advocates (see Hall v Simons).
… and things we don’t
However are we clear about which witnesses have lost their immunity? Lord Brown attempted to mark the boundaries (‘For the purposes of this brief judgment I mean by “an expert witness” a witness selected, instructed and paid by a party to litigation for his expertise and permitted on that account to give opinion evidence in the dispute. I am not referring, for example, to a treating doctor or forensic pathologist, either of whom may be called to give factual evidence in the case as well as being asked for their professional opinions upon it without their having been initially retained by either party to the dispute’).
Lord Phillips (para 18) drew the ‘significant distinction’ between the expert who chooses ‘to provide his services and will voluntarily have undertaken duties to his client for reward under contract’ and the witness of fact who has ‘no such motive for giving evidence’.
However in her dissenting judgment, Lady Hale said ‘there will be some professional witnesses who enjoy immunity in respect of their evidence and some who do not. Some of those distinctions will appear arbitrary.’ (para 187). She was ‘unclear whether the exception [to witness immunity] would apply only in a case where there was a contractual duty or whether it would apply in a case where there was no contractual duty but there might be a duty owed in tort’ (para 179). Indeed.
Will there be a flood of cases against expert witnesses?
Lord Phillips did not think that removing expert witness immunity would lead to a proliferation of vexatious claims: ‘It will not be viable without the support of another expert’ and ‘I am not aware that since Hall v Simons barristers have experienced a flood of such claims from disappointed litigants.’ (para 59).
How far does the advocate/expert take us? To sue his advocate successfully a client ‘would have to prove not only that the lawyer had been negligent but also that his negligence had an adverse effect upon the outcome. This would usually mean proving that he would have won a case which he lost’ (per Lord Hoffman in Hall v Simons). A client will find it easier to argue a causal link between the outcome of a case and the expert evidence than between the outcome of the case and the advocacy, particularly if the trial judge makes adverse comments on the expert witness’s evidence.
Will there be a chilling effect?
Lord Phillips (para 54) said ‘The case that immunity is necessary to prevent a chilling effect on the supply of expert witnesses is not made out.’ Expert witnesses already face the risk of being made the subject of a non-party costs order (Phillips v Symes (No 2)  EWHC 2330 (Ch),  1 WLR 2043 ) or being reported to their professional body (Meadow v General Medical Council  QB 462). However both these cases could be said to be extreme examples of expert witnesses losing sight of their duties to the court. It may be infinitely more ‘chilling’ for the expert witness to know that they may now be sued in negligence by their client if, under the pressure of cross-examination and thinking on their feet, they fail adequately to explain their opinions, despite Lord Brown’s assertion (para 85) that ‘it is very hard to envisage circumstances in which performance in the witness box could be the subject of even an arguable case’.
The difference between a barrister and an expert witness
Telling a barrister he may be sued by his client for negligence is a bit like telling the adventurer Bear Grylls that he may be left in the middle of the desert with only a bottle of water and a Swiss Army knife. He won’t relish the prospect, but he can rely on his training and his experience to survive.
In contrast expert witnesses have no standard system of accreditation or training for court work and most experts do it as an ‘add-on’ to their full-time job.
As Lord Hope said:
‘It is one thing to be liable to a wasted costs order at the instance of the court itself or to proceedings by a professional body for professional misconduct. It is quite another to be at risk of worthless but possibly embarrassing and time-consuming proceedings by a disgruntled and disaffected litigant in person. Insurance cover, if available, is not a universal remedy.’ (para 165)
The risk/reward calculation of the publicly funded expert witness in family proceedings is very diferent compared to that of the privately funded expert in commercial litigation. The risk has just increased at a time when legal aid funding rates are being capped so if there is to be a chilling effect, it may be most acutely felt in the family courts. Back in 2006, the then Chief Medical Officer, Sir Liam Donaldson, in his report ‘Bearing Good Witness’, flagged up a chronic shortage of expert witnesses. There still is one.
Lady Hale has called the outcome ‘experimental’ (para 190). Lord Hope and Lady Hale thought the better course of action would have been for the Law Commission to review witness immunity. We await the results of the experiment.
Professor Penny Cooper is Associate Dean at The City Law School, City University London and Governor of The Expert Witness Institute