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Expert Witnesses: Liability to Parties Other Than the Client

Medico Legal

by Dr Anton van Dellen - Barrister, Goldsmith Chambers


It is now over five years since the seminal case of Jones v Kaney [2011] UKSC 13 which introduced liability for expert witnesses. Unlike lay witnesses, who have maintained their immunity, expert witnesses are now liable in negligence and may be sued by disgruntled instructing parties. This followed the loss of immunity of barristers a decade prior in Hall v Simons [2002] 1 AC 615.

At the time of Jones v Kaney, scepticism was expressed that removal of expert witness immunity would trigger a flood of vexatious and unmeritorious claims. This was a view expressed by Lord Phillips at [59], drawing a direct parallel with the experience of barristers following the loss of barrister immunity.

However, as soon as seven months after Jones v Kaney, concern was already being expressed that the predicted trickle of claims was an under-estimation of the likely scale of litigation against expert witnesses.1

The approach of the Court of Appeal since Jones v Kaney

Ridgeland Properties Ltd v Bristol City Council [2011] EWCA Civ 649 was a decision which followed shortly after Jones v Kaney. In circumstances where an expert witness forgot to mention a key piece of evidence, Sullivan LJ held at [47] that such an omission could trigger a claim by the party instructing the expert against that expert, provided that the instructing party had acted with due diligence by assisting the expert in every way he can, such as by providing the expert with all relevant facts and information and allowing the expert to discharge his duty to the Court or Tribunal.

However, focussing on the duty of care of an expert witness encounters several problems, as discussed by David Capper.2 Jones v Kaney addressed the issue of an expert instructed by a party who breached their duty of care to that party.

But, it is not difficult to envisage scenarios where this basic paradigm would not apply. The most obvious example is a single joint expert who owes a duty of care to each party. Another example, noted by Baroness Hale in Jones v Kaney, is an independent psychiatrist instructed on behalf of the patient in tribunal proceedings under the Mental Health Act 1983, or the child psychologist or child psychiatrist instructed by the parents of a child with special needs in proceedings before a Special Educational Needs Tribunal. There is an obvious discrepancy between the party instructing the expert and the party to whom the duty of care of the expert applies. Likewise, it is also not clear whether social workers who carry out expert risk assessments have a duty of care to the local authority that instructs them or to the parties in the proceedings.

Capper raises a far more fundamental problem relating to the expert’s duty of care, which is that the expert owes an overriding duty to the court. Ultimately, this may potentially mean that the expert will relegate his duty of care to his client. However, by acting in this manner, the expert is not falling below a reasonable standard of care for an expert witness and a claim for professional negligence would probably be doomed to fail.

What core immunity remains despite removal of liability for expert witnesses?

Despite Jones v Kaney, there remains a core of immunity which appears to be retained by expert witnesses, as per Spencer J in A v Chief Constable of Hampshire [2012] EWHC 1517 (QB). The dispute in that case related to various disclosures made during the course of proceedings. The core of immunity appears to cover disclosure in the course of providing expert evidence. At [26], Spencer J held (underlining in the original; bold added):

… The Supreme Court in Jones v Kaney cannot be taken to have intended to abolish the core immunity under examination in the present case, which has been enjoyed by witnesses, parties and their advocates for centuries. … Jones v Kaney is concerned with the liability of a “friendly” expert to the party who instructed him. Arthur JS Hall v Simons was concerned with the liability of an advocate to his own client.…

Consequently, it would appear that disclosure such as that in A v Chief Constable of Hampshire would be protected by core immunity and would not be caught by Jones v Kaney liability. Consequently, not all actions by an expert witness appear capable of triggering liability – disclosure would not automatically be a breach of the reasonable standard of an expert witness. By contrast, an opinion expressed in relation to that disclosure would potentially be a breach of the reasonable standard of care.

Liability for costs outside the regime of Jones v Kaney

Peter Smith J in Phillips v Symes [2004] EWHC 2330 (Ch), which obviously predates Jones v Kaney, ordered wasted costs against an expert in a decision that anticipated the approach of the Supreme Court in Jones v Kaney. Phillips v Symes was cited in Jones v Kaney by Lord Phillips PSC at [44], who held that the utility of the expert’s exposure to wasted costs was that it would act as a deterrent to an expert who erred in the process of balancing their duty to their client to their duty to the court:

44. … In Phillips v Symes (No 2) [2005] 1 WLR 2043 Peter Smith J held that expert witnesses were not immune from being held liable to wasted costs orders. .... I do not consider that the susceptibility of expert witnesses to disciplinary proceedings or to wasted cost orders weakens the case for immunity from civil suit, in so far as this case exists. The principal argument advanced for immunity from civil suit is that the risk of being sued will deter the expert witness from giving full and frank evidence in accordance with his duty to the court when this conflicts with the interests of his client. In so far as a witness may be tempted to trim his sails to suit his client, I would expect the risk of disciplinary proceedings or of a wasted costs order to be a deterrent. …

In Phillips v Symes, it was suggested at [22] that the threshold for wasted costs against an expert (on the basis that they had breached their duty to the court) was if “they act in flagrant disregard of that duty”. At [23], it was suggested that the threshold is a “gross dereliction of their duties”.

The authority to order wasted costs against an expert in Phillips v Symes was also held to derive from the judgment of Lawrence Collins QC (as he then was) sitting as a Deputy High Court Judge in Locabail (UK) Ltd v Bayfield Properties Ltd [2000] 2 Costs L.R. 169. However, the threshold in that case for ordering costs against a non-party was held to be if it was “just and reasonable to do so”, relying on the earlier case of Symphony Group Plc v Hodgson [1994] Q.B. 179 (CA).

Symphony Group outlined a number of points of principle in relation to the making of costs orders against non-parties, the first two of which are of particular relevance for expert witness and are expressed as being an obvious application of the basic principles of natural justice:

(1) An order for the payment of costs by a non-party will always be exceptional, as per Lord Goff in Aiden Shipping Co. Ltd v Interbulk Ltd [1986] A.C. 965 , 980F.

(2) The party seeking their costs should warn the non-party at the earliest opportunity of the possibility that he may seek to apply for costs against him. At the very least this will give the non-party an opportunity to apply to be joined as a party to the action.

The approach of making a wasted costs order against an expert was followed in X Local Authority v Trimega Laboratories Ltd [2014] 2 FLR 232, when the basis for making such an order was held to derive from the Senior Courts Act 1981 s.51, the Civil Procedure Rules r.46.2 and the Family Procedure Rules 2010 Pt 28. The court in Trimega held that the test need not be as high as a flagrant, reckless disregard of the duties of an expert but that even a simple human error can suffice to warrant the ordering of wasted costs against an expert. Costs of £17,167 were ordered to be paid in that case.

Finally, in Re Capita Translation and Interpreting Ltd [2015] EWFC 5, Sir James Munby PFD held at [21] and [31] that, under section 51 of the Senior Courts Act 1981, a non-party could be ordered to pay costs of that party failed to attend and the hearing was consequently not effective. Capita obviously involves the failure of attendance of an interpreter, but the reasoning is equally as applicable to an expert witness. The liability is not necessarily to the party instructing the expert witness, but would include the other parties in proceedings. Of note is that Sir James Munby expressly endorsed the approach of Peter Smith J in Phillips v Symes.

However, overall, given the seniority of the court, the approach of Symphony Group is probably to be preferred.


Several issues of uncertainty in relation to expert witness liability remain unresolved despite the passage of time since Jones v Kaney. The first relates to circumstances where the expert owes a duty to a number of parties, rather than just one. The second relates to a core form of immunity which appears to remain untouched despite Jones v Kaney. The third is the pre-existing regime allowing wasted costs against an expert witness, the threshold of which remains wholly unclear. Given this uncertainty, the approach of the Court of Appeal in Symphony Group is to be preferred, namely that an order for the payment of costs by a non-party will always be exceptional.

Dr Anton van Dellen

Barrister, Goldsmith Chambers

BPP University Schools of Law and Health

Conflict of interest: Dr Van Dellen delivers expert witness training on behalf of BPP University and the Royal Society of Medicine. The views expressed in this article are his alone and not those of BPP University or the Royal Society of Medicine.


1 Van Dellen, “The Aftershock” NLJ, 2011, 161(7488), 1523-1524.

2 David Capper. “Professional liability in the trial process”, P.N. 2013, 29(1), 7-24.

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