Professor Poston has maintained an active medico-legal practice since 1995, initially working in the field of personal injury, but more recently predominantly in the field of clinical negligence.
He has provided over 800 reports to the Court dealing with issues of liability, causation, condition and prognosis on cases of alleged clinical negligence. His areas of expertise in these cases include abdominal surgery, surgical gastroenterology and in particular the surgery of the liver, gallbladder and bile ducts, the acute abdomen, hernia surgery, and lastly loss-of-chance in cases of missed cancer diagnosis. His personal injury cases relate to soft tissue injuries and post-traumatic hernia.
In giving evidence as an expert witness, although thankfully infrequent, you must be prepared to present your evidence under oath to the Court and be cross-examined on your opinions. Such hearings include those to the civil courts, the criminal courts, the coroners’ courts, the General Medical Council, and increasingly since the pandemic, giving evidence virtually by video link. When starting a medico-legal practice, in addition to attending courses on report writing, it is absolutely essential to attend courses on presenting your evidence in court under mock cross examination before your peers. Even experienced medico legal experts should periodically attend update courses on report writing and courtroom skills as the law not infrequently changes.
CIVIL COURT
If a civil claim proceeds to litigation, then it is possible if you and your opposite number cannot agree your opinions that it might end up in Court. It is possible that the claim is of such low value that the parties might agree a commercially based settlement without accepting liability, in order to avoid prohibitive courtroom legal fees. However, as litigation proceeds and the possibility of going to Court increases then about 12 months before the potential trial, you will be asked to provide your dates of non-availability (with good explanations) within a 2–3-month trial window.
Once the availability of all essential parties is agreed then the Court will establish the trial dates (usually over 3-5 days for a clinical negligence claim) and you will then receive a witness summons. Failure to heed this summons will result in criminal charges of contempt of court. You must clear your diary for the trial dates, take unpaid leave since if the trial proceeds, then you will be paid your agreed daily rate (+/-VAT) for attending court (and make sure your pre-trial cancellation terms are clearly stated when you take initial instruction, including cancellation fees 8-14 days pre-trial and cancellation fees 1-7 days pre-trial). If after the preparation of the experts’ Joint Statements, there are still significant differences between you and your opposite number then the claim is likely to proceed to trial and you will need to attend a pre-trial conference with Counsel. You can and may have to attend the whole trial, which in clinical negligence cases are usually in public.
At trial, make sure that you have fully familiarised yourself with the paginated trial bundle containing all the witness statements, expert reports, references contained within the reports, Particulars of Claim and the Defence. These bundles usually involve several A4 lever arch files to which each party will have access, as will the judge, and a further bundle will be beside you in the witness box.
Either take the appropriate oath or affirm, and when giving evidence, address the judge, not the barrister examining you. Give your evidence very slowly, as the judge will either be writing it down long-hand or typing it as you speak, and address the judge as ‘Judge’. When examined, give short answers, not long rambling responses. Don’t get into arguments with the opposing barrister. Remember, you are there to give an independent expert opinion to the Court, not as an advocate for your instructing party (that is Counsel’s job). When taking a break while giving evidence (lunch or overnight) you must not discuss your evidence with anyone at all, including instructing lawyers, family or friends.
Remember, it is opposing Counsel’s job to try and catch you out and they will structure their questions around your written evidence in such a way as they will expect single one-word answers of yes or no. if you disagree with the opposing Counsel then be prepared to explain your position directly to the judge, not Counsel.
There are a number of pitfalls that Counsel might set at the start of your evidence in order to damage your credibility to the Court. The first relates to Part 35 of the CPR, to which you will have stated at the end of your Part 35 compliant disclosed report that you understand the duty that you owe to the Court, that you have complied with that duty, and will continue to comply with that duty. You are aware of the requirement of the CPR Part 35, Practice Direction Part 35, the Practice Direction on Pre-Action Conduct and the Protocol for the instruction of Experts to give evidence in Civil Claims. Therefore, it is not unreasonable for Counsel to preface your cross-examination by asking you to explain your understanding of Part 35 of the CPR to the Court, so make sure that you have read it immediately before giving your evidence.
Furthermore, you will have signed your Statement of Truth that you confirm that you have made clear which facts and matters referred to in this report are within your own knowledge and which are not. Those that are within your own knowledge you confirm to be true. The opinions you have expressed represent your true and complete professional opinions on the matters to which they refer. You understand that proceedings for contempt of Court may be brought against anyone who makes, or causes to be made, a false statement in a document verified by a statement of truth without an honest belief in its truth.
Lastly, regarding civil clinical negligence trials in England and Wales, make sure that you are fully conversant with the Bolam test, Bolitho test and the Montgomery Ruling of the Supreme Court, since again, these are questions that opposing counsel can legitimately test your understanding. Similarly, if giving evidence in a Scottish Court then make sure you understand the principles of Hunter versus Hanley and likewise in an Irish Court, the Dunne Principles.
CRIMINAL COURT
You may be attending the criminal court either as a witness to fact or as an expert witness. As with civil hearings, criminal court proceedings are usually (but not necessarily) in public. As with a civil trial, having affirmed or taken the appropriate oath, give your evidence slowly to the judge, not the examining barrister or the jury. You may or may not be cross examined, but as with civil cases, you are there as a witness, not an advocate for either side. As with civil trials, you may be called or recalled at any point during the trial, which unlike civil clinical negligence trials can last many weeks, so don’t book any holidays during the anticipated trial dates.
CORONERS COURT
As with civil trials, hearings are heard in public. Again, as with civil and criminal hearings, you will be giving your evidence under oath and give your evidence slowly. This hearing may be about a deceased patient who was under your care, in which case you might be well-advised to have legal representation (provided either by your NHS employer or your medical defence organisation). On the other hand, if you are giving expert evidence to the coroner then you do not need your own legal representation. In any event, the family of the Deceased might have legal representation by either a solicitor and/or a barrister who may examine you under oath. You are there to advise the coroner in reaching a verdict on the cause of death. You can be critical of the treatment received by the Deceased, but you are not there to opine on issues of breach of duty and/or causation. Furthermore, remember that coroner’s budgets are limited, so don’t overcharge!
THE GENERAL MEDICAL COUNCIL
The GMC’s Medical Practitioners Tribunal Service (MPTS) is based in Manchester and runs all medical practitioner tribunal hearings for doctors registered in the UK. Many hearings are heard virtually, and most are heard in public. When instructing you to give evidence, the MPTS will take your availability into account when scheduling the hearing, usually 4-5 weeks before the hearing is due to be held. The MPTS will usually ask you to keep several days free until they know the exact date and time of your attendance, so if you are employed by the NHS then arrange appropriate leave and cover. If it is a face-to-face hearing then on arrival at the MTPS reception, you will be taken to the main witness waiting area where you will meet the GMC’s instructed barrister. Remember, the doctor under investigation may also be seated in this area. Do not discuss your evidence with anyone else seated in the waiting area. You will be giving your evidence to 12 members of the GMC’s MPTS, usually 6 doctors and 6 lay (usually lawyers) seated at the top of a single table, with the GMC’s legal team seated down one side and the doctor under investigation and their legal team down the other side. Address your evidence to the Chair. The doctor under investigation and/or their legal representative(s) have the right to ask you questions about your evidence.
GIVING EVIDENCE TO A VIRTUAL HEARING
Virtual hearings are a product of the pandemic and while the structure of the hearing follows that of face-to-face hearings in the civil, criminal and coroner’s courts, there are certain ground rules that are necessary to follow. Firstly, in civil trials, there will be a virtual pre-trial conference with Counsel, and on each day of the trial, there may be a short pre-trial and post-trial virtual conference with Counsel to go over that day’s proceedings. Avoid using Wi-Fi if at all possible. Connect your laptop to the router with a cable. Ideally, lock the door of the room you are using to give evidence. No one must listen in. Seat yourself in a well-lit room in front of as blank a wall as possible. The Court does not want to be distracted by pictures of your family, pets etc. Make sure you are properly dressed both above and below the waistline! Remember, you may be required to stand when the judge enters or leaves. However, cross examination is less daunting in virtual hearings since you are being examined over a video link and not face-to-face in an open courtroom.
Remember, in all roles as an expert witness, your duty is to the Court.
For more information about training as a medical expert witness please see the SpecialistInfo range of CPD courses, including Courtroom Skills: https://www.specialistinfo.com/course-calendar-2025
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