In Thefaut -v- Johnson [2017] EWHC 497(QB) Mr Justice Green made some important observations about the need for experts to be candid about their prior knowledge of, and relationships with, the parties to the action.  A failure to mention knowledge of a party did not affect the outcome of this case but it clearly led to time being spent in vigorous cross-examination.

“…it is my view that Mr Gullan would have been far better to get out in the open his personal knowledge of Mr Johnston. A concise but accurate and comprehensive paragraph in his report setting out the bare facts of his knowledge of Mr Johnston would have sufficed. This would have taken much of the sting out of the cross examination”


The claimant brought a claim in negligence against the defendant surgeon. Both sides called experts. Both sides attacked the integrity of the other’s expert.

    1. “Observations about the expert evidence that I received on this issue:
(i) Mr Kirkpatrick (for Mrs Thefaut) was of the opinion that the exposure of the nerves was an abnormal fact in the case and causative. He accepted that he had little experience of performing revisional surgery of the sort performed by Mr Samandouras. He did however construe the medical records as indicating that Mr Samandouras came across the breach of the dura but did not cause it himself and that therefore it was Mr Johnston who necessarily caused the dural breach. This was based only upon his reading of the documents. In terms of the effect of a breach he considered that the breach was likely to have occurred as a consequence of a surgical procedure and would mean that “… the nerve root is exposed to scar formation etc…“. In the Joint Experts Agenda (prepared on behalf of the Claimant), Question 54 addressed the impact of any scarring over exposed nerves. The answer given (agreed to by both experts) was: “Although neither expert has direct confirmation of this, we believe that targeting of a nerve root which is not protected by a dural sheath, is likely to be a more obvious source of neuropathic pain syndrome“.
(ii) Mr Hyam QC launched a sustained attack on the professionalism of Mr Kirkpatrick. This arose because Mr Kirkpatrick had in two recent cases, one in particular involving a claim for negligence against Mr Johnston which ultimately failed, been subject to serious criticism by the Court for his conduct as a professional expert witness: See e.g. Harris v Johnston [2016] EWHC 3193 (QB) per Andrews J.
(iii) More or less the full extent of the views on this important issue from Mr Gullan was in the expert’s Joint Statement where he stated: “Mr Gullan has some difficulties with this concept bearing in mind in re-visiting operations, the anatomy can become extremely indistinct“. He elaborated in far greater detail when giving oral evidence. He said that in a significant number of revisional procedures (of which he did many) there was an ever-present risk of breach of the dura. He considered the actual evidence based upon the account of Mr Samandouras to be unclear. He said that he had never seen “free floating” nerves in his career (though he did not comprehend what that term could actually imply or mean) but that a breach of the dura was not uncommon and not necessarily negligent; it all depended. He considered that if there was a breach it was in all likelihood attributable to Mr Samandouras.
(iv) Mr Peacock (returning fire) launched an attack on the professionalism of Mr Gullan upon the basis, inter alia, that he had failed in his report to record his prior knowledge of Mr Johnston as a colleague on various professional bodies and his regard for Mr Johnston as a surgeon of repute and skill. This was an omission going to his impartiality. He also attacked Mr Gullan upon the basis that although the issue of the findings by Mr Samandouras had been an important part of the litigation from the date of the Letter of Claim he had more or less ignored it and only really engaged with it for the first time when he gave oral evidence. He also attacked Mr Gullan for not appearing to have been aware of the actual evidence that Mr Samandouras gave in the witness box, which preceded his own evidence.
(v) In the event I took the course that I should simply listen with care to the expert evidence given by both of these experts and to the extent that there was a dispute between them I would then bear in mind any criticisms of their professionalism which I thought well founded and relevant in forming my view on the issues in dispute. My ultimate conclusion was that both experts acted properly in the giving of their evidence. I have not felt the need to discount their views on the basis of any want of professionalism. I would however make one observation. In the specialist field in issue there are a relatively small number of surgeons. They tend to know, or know of, each other, especially if they have been in practice for many years and have had prior involvement with each other as colleagues serving in the various specialist professional bodies. In such circumstances there is a high probability that when one of this select group is instructed to act as an expert in a case he or she may know of the Defendant either personally or by repute. This was the case of Mr Gullan in relation to Mr Johnston. He knew him both from co-participating in professional bodies and by repute. This did not in my judgment necessarily mean that he could not give expert evidence in the case. He was not so close to Mr Johnston that, objectively speaking, his independence was compromised. But it is my view that Mr Gullan would have been far better to get out in the open his personal knowledge of Mr Johnston. A concise but accurate and comprehensive paragraph in his report setting out the bare facts of his knowledge of Mr Johnston would have sufficed. This would have taken much of the sting out of the cross examination which did, I am bound to say, leave Mr Gullan feeling and sounding defensive. The issue here is the appearance of bias. The inevitable questions in cross examination which followed from the omission were along the lines that Mr Gullan was advancing a view which was tailored to support a fellow professional who was in a predicament, and hence lacked objectivity. If this had in fact been Mr Gullan’s intent and object when giving evidence it would have struck at the very heart of his professionalism and objectivity and it could have rendered his evidence inadmissible: see, e.g. EXP v Dr Charles Simon Baker [2017] EWCA Civ 63 at paragraph [49] per Irwin LJ. As I have observed I do not accept that Mr Gullan gave his evidence other than objectively and independently.”