Tips on expert evidence

Thea Wilson gives her tips on expert evidence in clinical negligence cases, considering the recent case of Robinson v (1) Liverpool University Hospital NHS Foundation Trust (2) Mercier.

It is no exaggeration to say that in clinical negligence, expert evidence will make or break your case. Perhaps more so than in any other field of litigation, success in a clinical negligence case depends on having a good expert in the right discipline; an expert whose report can be relied upon, and who can withstand rigorous challenge in joint discussions and under cross examination. The recent case of Robinson v (1) Liverpool University Hospital NHS Foundation Trust (2) Mercier (1 October 2021) is a helpful example of things going wrong at every stage of the process and of the consequences that can follow when it does.

Choosing the expert:

The first question when building or defending a case is: which discipline(s) is/are required? Whilst this may seem obvious from the facts, it is important to consider the nature of the injury (e.g. is a psychiatric injury more suited to a psychiatrist or a psychologist?) and whose breaches need to be investigated (e.g. is the criticism of surgery, aftercare by medics or the nursing care?). In Robinson v Mercier one of the main criticisms of the claimant’s expert was that, as a general dental practitioner, he expressed an expert opinion on the standard of care afforded to the claimant by an oral and maxillofacial surgeon without apparent consideration of whether they would have the same duty of examination, access to the same equipment, or the same medical questions to consider.

As a defence lawyer, the task is often easier: generally, a defendant will want to fight fire with fire on the main areas of expertise relied upon by the claimant. But it is important to take a fresh look and decide whether the claimant has in fact chosen the right discipline of expert.

The second question is: which expert within that discipline? This may depend on cost and availability, but nothing beats personal experience and recommendations. Check important factors like: is the expert still practising, or retired from NHS practice? Have they got practical and recent experience of the issues? Is this their particular speciality? Have they got court experience? Have you, or others you trust, seen them in conference and/or in court? Do they have a mixed location practice (e.g. a plastic surgeon practising in the UK and abroad), and, if so, are they able to distinguish the standards expected in England and Wales versus the standards in another country? Even with recommended experts, check their current position and any links to the parties. In Thimmaya v Lancashire NHS FT (30th January 2020, Manchester County Court), the defendant’s wasted costs were awarded against an expert who had only revealed under cross-examination that he had suspended his clinical practice 18 months previously due to psychiatric difficulties which impaired his ability to give evidence; the claimant was forced to discontinue the case. In EXP v Barker ([2015] EWHC 1289 (QB)), on the defendant’s personal recommendation, his legal team used an expert witness (M), who turned out at trial to be a long-time colleague of the defendant, who had trained him for seven years and written at least one paper with him.

Whilst it may be tempting to reach out for a “gun for hire” who will be a big supporter of the case no matter what, in reality these experts are more of a hinderance than a help. One of the criticisms of Dr Mercier by the court in Robinson (ibid) was that “His opinion fluctuates to whatever he feels will win the case.” What the court wants, and what will serve a party best, is an expert who is independent (assisting the court rather than acting as an additional advocate); reasonable (making concessions where appropriate but standing firm otherwise); can justify their opinions with evidence and clear reasoning, not hunches and unexplained theories; and who stays within the boundary of their expertise.

Testing the expert:

Once you have the report, it is vital to test it. Firstly, does it comply with the requirements of Part 35 and Practice Direction 35 (it is astonishing how often errors come to be made and/or experienced experts do not stay abreast of updates to those sections when they change)? Secondly, is it readable or does it unnecessarily quote large sections of literature or other reports (see Harman v East Kent Hospitals NHS Foundation Trust [2015] EWHC 1662 (QB) per Turner J)?  Thirdly, does it report the facts accurately and without omissions? Fourthly, are the conclusions on breach, causation, and/or condition and prognosis explained and is it possible to understand the logic of those explanations? Lastly, have the legal tests been properly stated and considered (see Harris v Johnston ([2016] EWHC 3193 (QB))?

In Robinson v Mercier, the judge identified that there were major gaps in Dr Mercier’s report which should have set off alarm bells for the claimant’s legal team, including that he had not: seen an x-ray which was later described as fundamental to the experts’ analysis; explained why he considered the claimant’s condition 18 months after the surgery was evidence of her tooth’s condition immediately before the surgery; or, crucially, addressed the relevant legal test for breach of duty. The Judge considered that the “report itself reaches wholly unsustainable conclusions”.

In clinical negligence, in all but the smallest cases it will be necessary to hold a conference with the expert. In conference, it is vital to properly test the expert: to ask what the other party’s expert will say and why; to get them to explain, with reference to literature if possible, why the conclusions reached in the other side’s report are wrong; to check that the expert understands the legal tests to be applied; and to confirm that they have had access to all important documents (including the pleadings and any witness statements).

Prepare for joint statements:

Make sure your expert is clear what the issues are before joint statement stage. Identify the weaknesses in reasoning in both parties’ reports in advance, in conference if it precedes the joint statement stage. In larger cases, consider agreeing an agenda, or at least a list of topics, for the experts to consider. Encourage the expert to ensure that the joint statement is not simply a cut-and-paste of the key passages of the competing reports’ opinion sections, but engages with and answer the opposition’s case. Make sure that the expert has read the joint statement before signing it (this may seem obvious, but see Holdsworth v Luton & Dunstable University Hospital [2016] EWHC 3347 (QB)).

At trial:

If possible, get the expert to hear not only the other expert evidence, but also the witness evidence on the relevant topic (the need for this should be borne in mind at budgeting stage). The expert will be giving opinion evidence which may be highly dependent on the facts that the Judge has to decide. If something new comes out in oral evidence, it should not take the expert by surprise in the stand. If, for budgetary or availability reasons, an expert cannot hear witness evidence, ensure that a full note is available to the expert as far as possible in advance of them giving their evidence. Use the expert to assist with cross-examination of the opposing expert and prepare them, if necessary, for the court hot-tubbing the experts.

What if it all goes wrong?

What do you do if, even after following the above tips, disaster strikes and the expert lets you down? Pre-trial a late change of mind or wavering by the expert should first be addressed in conference or at least with questions of the expert. Explore the background to the change of mind and enquire into their reasons (any failure to respond to such enquiries would support an argument that the expert had not acted properly). Switching experts is possible, but harder the closer to trial you get. Courts will also not allow a change of experts merely because they no longer support a case; but if the enquiries show that the expert has stepped outside their expertise or shown themselves to be incompetent, that may justify a change (see Stallwood v David [2007] 1 All ER 206).

If an expert destroys the case through a late change of heart or at trial, particularly if it becomes clear that their original advice was based on unsupportable reasoning, consider whether to pursue a claim against the expert (or for costs against the other party’s expert if appropriate). In Robinson, Recorder Hudson awarded the defendant NHS Trust their wasted costs, holding that an expert witness was not immune from the sanction of compensating those who had suffered by evidence given recklessly in flagrant disregard of the expert’s duties to the court. He held that it should have been obvious to Dr Mercier at the outset, and at various stages throughout the proceedings, that he was not the appropriate expert. He was found to have not made any efforts to assist the court, but instead to have wilfully stuck to his case theory irrespective of the questions asked or the evidence given. His evidence was held to be grossly unhelpful and wholly unreliable, showing a flagrant reckless disregard for the duties of an expert to the court. Having found a case in negligence established, Recorder Hudson considered whether there was a causal link to the loss. He held that, despite Dr Mercier’s attempt to lay the blame on the claimant’s legal representatives for concocting a case out of his report, but for the initial report the claim would not have been brought and the NHS Trust would not have been put to considerable expense defending it. Such an order was therefore just.

Overall, although it is a more extreme example, Robinson is a cautionary tale on the pitfalls that can arise in expert evidence in clinical negligence cases.