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Edward Henry KC name

Challenging an expert


In Criminal litigation experts are rarely challenged as to whether they have the requisite expertise. It is not, for example, uncommon for a forensic psychiatrist, with no specialism in autism to be regarded as being competent to offer an opinion contrary to renowned experts in their field. Similarly, in a recent case, a psychiatrist, without neurological expertise, was held competent to contradict a cohort of experts who considered the defendant was unfit through brain damage.

The gateway, to permit the generalist, with no more than a sporadic or infrequent acquaintance with the specialist issue, to challenge specialist colleagues can be discerned by the succinct appraisal of Hodgkinson and James in Expert Evidence: Law and Practice ((4th edn.) Sweet & Maxwell, 2015; 8-002). The authors identify two qualifications that define competence for the expert witness: (1) familiarity with the specialist field relevant to the matters upon which the evidence is to be given; and (2) the requisite level of expertise, whether it is gained through learning or experience. ‘Familiarity’ is required to do some heavy lifting in the cases alluded to above. That said, it is possible to “acquire expert knowledge in a particular sphere through repeated contact with it in the course of one’s work, notwithstanding that the expertise is derived from experience and not formal training” (Malek, H.M. (ed) (2013) Phipson on Evidence (18th edn), Sweet & Maxwell; p.1189). Again, ‘repeated’ which I have emphasised above in bold, may be seen as a relative term.

Whether a proposed expert is entitled to be regarded as an expert remains a matter for the court, applying the principles reiterated by the Supreme Court in Kennedy v Cordia (Services) LLP (Scotland) [2016] UKSC 6. In this judgment Lord Reed and Lord Hodge adopted the approach in Daubert v Merrell Dow Pharmaceuticals Including (1993) 509 US 579 and referred to “a witness qualified as an expert by knowledge, skill, experience, training, or education.”

In Kennedy, Lord Reed and Lord Hodge stated: ‘The skilled witness must demonstrate […] that he or she has relevant knowledge and experience to give either factual evidence, which is not based exclusively on personal observation or sensation, or opinion evidence.”

This short piece concentrates on some tools for challenging psychiatric evidence. The GMC has provided useful guidance at:

Another great source for ideas is Prof Keith Rix’s magisterial work on Expert Psychiatric Evidence. He later co-authored, with Professor Nigel Eastman (now sadly deceased) and Dr Gwen Adshead, The Royal College of Psychiatrists’ Report CR193 Responsibilities of psychiatrists who provide expert opinion to courts and tribunals (‘CR193’), which is invaluable  Other papers he has authored can be seen in the checklist below.

Checklist for challenging Expert Psychiatric Evidence

  1. Has the witness clearly and transparently set out their expertise, justifying their competence? Under CrimPR 19.2(3)(a)(i), the expert’s duty to the court includes defining in his/her report his/her ‘area or areas of expertise’ and r 19.4(1)(a) states that his/her report must ‘give details of the expert’s qualifications, relevant experience and accreditation.’ The family case of In re C is instructive.

In Re C, McFarlane P said:

‘A lesson plainly to be drawn from the present case is the need for clarity as to an expert’s qualification and/or experience. The more diffuse and unstructured a CV, the less effective it is in transmitting information crisply and clearly. In this regard, lawyers, magistrates and judges are lay readers. They need to be able to see with clarity, and in short form, the underlying basis for an individual’s expertise.’

2. Have they demonstrated by virtue of knowledge, skill, experience, training, or education that they are qualified to offer an opinion? Familiarity is not enough, I would argue. Have they received specialist training, specialist clinical experience and also published?

3. Has the witness strayed outside their expertise? Psychiatrists are warned that they have “a duty to give testimony only in their area or field of expertise” and that they “have a duty not to give evidence or opinion on matters outside their areas or fields of expertise” (CR193). Furthermore, in the context of preparation for their annual appraisal, which in turn informs the processes of revalidation and relicensing by the GMC, the College states: “There is also a duty on them to show that they have maintained their skills and competence in their field of expertise. They must be able to show to their responsible officer that they have demonstrable expertise in the field or fields claimed.”

4. Many expert witness psychiatrists felt concern following the decision in Pool v General Medical Council [2014] EWHC 3791 (Admin), [2014] 11 WLUK 347 in which a psychiatrist fell into regulatory error by going beyond his expertise. Additional guidance on this useful case can be found in:

a. Rix, K., Haycroft, A. & Eastman, N. Danger in deep water or just ripples in the pool: has the Pool judgment changed the law on expert evidence? BJPsychAdvances 23, 347-357, 2017.

b. Rix K., Eastman, N. and Haycroft, A. After Pool: good practice guidelines for expert psychiatric witnesses. BJPsychAdvances 23, 385-394, 2017.

5. Finally, has the witness set out their methodology, in accordance with CrimPR 19.4(1)(h)?


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