In the latest of a number of High Court judgments in which judges have strongly criticised an expert witness in a clinical negligence case, Mr Justice Martin Spencer took a consultant neurosurgeon to task in Arksey v Cambridge University Hospitals NHS Foundation Trust  EWHC 1276 (QB):
‘In my judgment, Mr Sandeman’s evidence fell far below the standard to be expected of a reasonable, competent expert witness, both in relation to the preparation of his reports and in relation to his preparing to give evidence. I could see no excuse for this whatever... In the end, the continual apologies... were embarrassing... his oral evidence was unimpressive. It was intemperate, at one stage he even used an expletive, and there was a failure on his part to address the questions that he was being asked...’ 
Neurosurgeons seem to have borne the brunt of judicial displeasure in recent years, but others are not immune. In YAH v Medway NHS Foundation Trust  EWHC 2964 (QB) Mrs Justice Whipple demolished the expert evidence from a psychiatrist who
has, over the years, provided hundreds of expert reports in clinical negligence cases:
‘I found her to be overly dogmatic about the classification of mental illness, at the expense, at times, of the evidence. I was not impressed by her stated preference for working for Defendants and the reasons she gave for doing so. I was not impressed by her inclusion of the hospital records in her report as “seen” in circumstances where she accepted that she had not read them at the time she authored her report. I was not impressed by her defensiveness in answering questions about those records…’ 
Litigators may have to take some responsibility when expert evidence goes awry. Martin Spencer J observed in Arksey:
‘I do not altogether exonerate the lawyers who have represented the claimant because they allowed Mr Sandeman to go into the witness box despite these clear and obvious deficiencies in Mr Sandeman’s written evidence, and this was something which should have been addressed by the lawyers long before the trial.’
Speaking at the Expert Witness Institute annual conference in London in September 2019, Lady Justice Nicola Davies warned against parties using experts who had been retired from clinical practice in the NHS for too long. They risked being regarded as
‘dinosaurs’. At the same event, Martin Spencer J said: ‘As a judge, it’s not enough for me to have an expert who knows everything about neurosurgery. It’s useless if he hasn’t done his job as an expert.’
Expert evidence is necessary in all clinical negligence cases, but advice on good practice applies to the use of experts in all forms of litigation. For litigators as well as experts, the recent judicial criticisms emphasise the following practice points:
Choice of expert
- The expert should have the appropriate qualifications and experience to provide opinion evidence in the case. For example, it is not sufficient merely to select a psychiatrist for a psychiatric negligence case. Practitioners should have regard to
whether the expert has experience relevant to the particular condition or treatment under consideration.
- The expert giving evidence on liability should be in clinical practice within the NHS, or have recently retired. One exception to this rule might be where the events in question in the case occurred many years previously. In such cases it may be necessary
to call opinion evidence from an expert who was in practice at the relevant time.
- The expert’s medico-legal practice should not be imbalanced in favour of claimants or defendants.
Instructing an expert
- Inform the expert of the legal tests for negligence and causation and the issues they need to address. Provide them with any available witness statements and pleadings. A common, comprehensive, paginated bundle of medical records should be provided
to which all experts and lay witnesses can refer.
- Prior to exchange of expert evidence ensure that your experts have seen and taken into account each other’s reports. Experts should defer to the opinion of another where the issue in question is outside their own field of expertise. Check that
the opinions, taken together, are consistent and coherent. If not, then differences of opinion will have to be explained within the reports.
- Check that the expert has accurately reflected the factual evidence that has formed the basis of their opinion. Correcting errors later in the proceedings, and especially at trial, is never impressive.
Prior to exchange of expert evidence
- Ensure that the expert has taken into account the other party’s case and commented upon it.
- Ensure that the expert has applied the proper legal tests such as ‘the balance of probabilities’. It is astonishing how many expert witnesses for clinical negligence claimants misunderstand the Bolam test or the balance
of probabilities, using unhelpful phrases such as ‘the care was sub-optimal’ or ‘on the balance of probabilities the negligence may have caused the injury’.
- Check the published papers/studies relied upon by the expert. Do they support assertions made?
- Test the expert evidence in conference. For counsel it is a difficult balancing act between thoroughly scrutinising expert witnesses, and losing your client’s trust that you are acting in their interests. However, experts should know that attending
a conference involves more than picking up the telephone and answering questions. They need to be prepared to be challenged and to justify their opinions.
- Obtain your experts’ views of the other party’s expert evidence.
- Identify which issues are, or are likely to be agreed, and which remain in dispute.
- Prepare agendas for expert meetings that identify the remaining issues and ensure that the experts will address the relevant questions, but which are not a form of written cross-examination. The parties should agree a single agenda bearing in mind
the pertinent observations of Mrs Justice Yip in Saunders v Central Manchester University Hospitals NHS Foundation Trust  EWHC 343 (QB) at : ‘I can see no good reason why the parties were unable to agree a single agenda in this case. Perhaps greater input from Counsel may have assisted. The joint statement is an important document. It ought to be possible to read it and to understand the key issues and each expert’s position on those issues. Sometimes less is more as far as the agenda is concerned. Parties should adopt a common sense and collaborative approach rather than allowing this stage of the litigation to become a battleground.’
- A pre-trial conference with experts is invaluable.
- Experts ought to attend trial to hear other witnesses give evidence. What is said at trial does not always match what was in the exchanged written evidence.
- Experts giving evidence at court impress when they are obviously well prepared, answer questions directly, demonstrate an understanding of the range of opinion including the other party’s case, remain objective, keep to their own areas of expertise,
and can articulate their opinion succinctly and clearly.
There is currently no formal vetting process for the selection of experts. Subject to limited oversight from the courts, parties to litigation are entitled to choose the experts they wish within the appropriate fields of expertise. As a result it is often
only at trial that an expert’s authority and credibility is fully challenged, sometimes with devastating results. Legal representatives have to select the right experts and then work hard to ensure that they are fully prepared so that their
clients benefit from expert evidence of the standard they deserve.
The 2019 Bond Solon/The Times’ Annual Expert Witness Survey of 569 experts revealed: almost half had come across experts professing expertise in an area in which they are not qualified/does not warrant expertise; 60% thought judges should have the power to permanently disqualify
experts who do not understand their role; 70% said the instructing solicitor should be liable for costs if they fail to exercise due diligence in selection and instruction; 20% believed that retired professionals should not continue to act as
expert witnesses; 41% had come across an expert they considered to be a ‘hired gun’; 25% had been asked or felt pressurised to change their report in a way that damaged their impartiality by an instructing party