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Expert evidence in clinical negligence litigation

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By Mark Ashley & Katharine Taylor


Published 16 December 2021


Without expert evidence there is no clinical negligence litigation. Experts are at the heart of the process and occupy a unique and important role, one which carries significant responsibility. In this note we consider the extent of this role and its responsibilities, and we consider whether the pandemic could cause some expert witnesses to fall short of the required standard.  

The importance of independent expert evidence

Allegations of professional negligence against healthcare professionals must be supported, in writing, by a relevant professional with the necessary expertise. The Pre-Action Protocol for the Resolution of Clinical Disputes identifies the need for expert evidence, and it requires parties to state whether they have obtained supportive expert evidence. Upon a claim entering litigation the stakes are raised, as allegations made without the benefit of expert evidence can be struck out: see Pantelli Associates Limited v Corporate City Developments Number 2 Limited [2010] EWHC 3189 (TCC) and more recently Magee v Willmott [2020] EWHC 1378 (QB) which we comment on here.

But it is not enough for a party to have a piece of paper from, say, an independent doctor which appears to support their claim or their defence. The doctor must be able to provide competent, credible and independent evidence which can assist the Court. These requirements, and the dangers posed by experts who fail to meet them, were highlighted in a recent speech given by Lord Hodge, Deputy President of the Supreme Court, to the Expert Witness Institute (reported here and here).

As the reports of the speech show, Lord Hodge focused on a number of themes including:

  • Independence and impartiality. Reference was made to the Bond Solon Annual Expert Witness Survey from 2019 (reported here), the results of which showed that 41% of respondents felt that they had come across another expert witnesses they would consider to be a ‘hired gun’. Furthermore, 25% of respondents reported that they had been asked or felt pressurised to change their report in a way that damaged their impartiality;
  • Remarkably, it still needs to be said that expert evidence must be based on relevant expertise; and
  • Performance or professionalism. Expert witnesses owe their primary duty to the Court and must, directly and indirectly (through cooperation with others who are involved in the litigation) adequately discharge that duty.

Where an expert fails to meet these standards their evidence may not only be worthless, but it may also be harmful. Not only does it affect, perhaps fundamentally, the case of the instructing party but it may result in both parties (and the Court) wasting time, money and effort.

How ‘expert’ should the expert be?

For an expert’s evidence to have value it must be a product of expertise in the thing they are commenting on. In a case concerned with the technicalities of a recent knee replacement operation, an orthopaedic surgeon with no consultant-level experience of knee replacement surgery would provide far less valuable evidence than a surgeon who has specialised in this type of procedure for many years.

Medical practice is ever changing, so it is vital that the expert has recent or current relevant experience. The Covid-19 pandemic provides a case in point.

The pandemic imposed new working arrangements in many areas of clinical practice. GPs will have undertaken video consultations and far more telephone consultations, difficult decisions will have been made to defer necessary procedures, and treatment may have been affected by operational issues such as staff shortages or lack of capacity. There will be many cases where these factors are relevant to the standard of care. In Cattley v St John Ambulance Brigade [1988] and  Mullholland v. Medway [2015] the Court considered the issue of healthcare professionals acting in emergency situations. Mustill J also provided obiter support for this in Wilsher (page 20 para D) “full allowance must be made for the fact that certain aspects of treatment may have to be carried out in what one witness …… called “battle conditions”. An emergency may overburden the available resources, and, if any individual is forced by circumstances to do too many things at once, the fact that he does one of them incorrectly should not lightly be taken as negligence”.  

Many medical experts maintain, quite appropriately, large and busy medico-legal practices. The nature of medico-legal work is such that many who undertake it are clinicians who are at or near the end of their clinical careers. Clinical negligence claims which are closely linked to the pandemic response (for example, a claim arising from a clinical examination in an Urgent Care Centre, made more difficult and perhaps less effective because of increased PPE) requires evidence from experts with relevant expertise. A proportion of established medico-legal experts will find that they do not have sufficient relevant expertise in order to provide valuable evidence.

What should the expert expect from the solicitor?

The expert has wide-ranging duties, but these do not fall solely on the expert’s shoulders: they also rest to a large extent on the instructing party. Dulson v Popovych [2021] EWHC 1515 (QB) concerns an attempt to resile from an earlier admission of liability, because of a change in opinion from a nursing expert. The application was refused. Not only was the judge critical of the Defendant’s nursing expert for her failure to deal with important issues which the Judge did not agree were simply cross-examination points, but criticism was also levelled at the Defendant’s solicitors for failing to consider (prior to the admission) whether there might be factual evidence relevant to the expert’s opinion and to supply it to her. Similarly, in Arksey v Cambridge University Hospitals NHS Foundation Trust [2019] EWHC 1276 (QB) a claim failed because of poor expert evidence. The judge found he could “… not altogether exonerate the lawyers who have represented the Claimant because they allowed [the expert] to go into the witness box despite these clear and obvious deficiencies in [their] written evidence, and this was something which should have been addressed by the lawyers long before the trial.”

What if it all goes wrong?

A claim or a defence might fail because of inadequate performance by an expert witness. If so, what recourse does the affected party have?

The instructing party might have a claim in negligence or breach of contract against the expert (see Jones v Kaney [2011] UKSC 13), but it would be more difficult for the opposing party to bring such a claim (i.e. defendant suing a claimant’s expert). This can leave the opposing party with a large loss (e.g. legal costs which cannot be recovered from the claimant).  

One exception to this is Thimmaya v Lancashire NHS Foundation Trust [2020] P.N.L.R. 12, where an expert who failed to disclose medical difficulties which affected their work was ordered by the Court to meet the Defendant’s wasted costs of a trial which had to be abandoned. However, the facts of Thimmaya were exceptional. The judgment held no support for the proposition that an expert who merely conducts their work poorly, e.g. producing a poorly reasoned report for example or being poor in the witness box, should be held liable in costs to the successful party.

Another recent example of this is Liverpool University Hospital NHS Foundation v Mercier [2021] 9 WLUK 400. The underlying clinical negligence claim concerned a dental extraction performed in 2016 in an NHS hospital by an oral and maxillofacial surgeon. The procedure was done under general anaesthetic. The claim failed owing in large part of the Claimant’s expert evidence. The Claimant’s expert witness was a general dental practitioner had last performed general anaesthetic extractions in 2000. He had never done so in hospital and was not an oral and maxillofacial surgeon. The evidence he gave (described as “absurd” by the judge) did not come from a position of any expertise. Consequently, he was ordered to pay £50,543.85 towards the Defendant’s costs.

As with Thimmaya the costs order in Mercier was exceptional. Obtaining such an order requires a great deal more than concern at some aspects of the expert’s performance; the expert must have wholly failed to meet their duty to the Court and this must have resulted in loss. A speculative or weak application for costs against an expert will itself be a costly endeavour, a good example of which comes from the recent unreported decision of District Judge Obodai in Walker v TUI UK Ltd (16 September 2021). Here, a failed application for costs against an expert resulted in the Defendant having to pay the expert’s costs of responding to the application, costs which are likely to come to more than £40,000.

Concluding remarks

Expert evidence is vital in clinical negligence claims and experts must have relevant expertise. The new ways of working brought about by the Covid-19 pandemic may mean that some expert witnesses are unable to provide evidence because they do not have experience of these new ways of working.

It is vital that solicitors scrutinise their party’s evidence. A failure to do so can result in weak claims and weak defences proceeding to trial in cases which should have resolved long before and almost invariably on better terms.

Sometimes, despite best efforts a case will fail because of negligence on the part of an expert. It may be possible to seek compensation from the expert witness e.g. for breach of contract, and in exceptional cases the Court can order the expert to pay an opposing party’s costs. But if the claim against the expert is weak, or fails to meet the very high bar for non-party costs orders, it is the expert who may be entitled to their costs.