Providing witness statements or expert evidence as part of legal proceedings

Providing witness statements or expert evidence as part of legal proceedings


Good medical practice sets out the principles, values, and standards of care and professional behaviour expected of all medical professionals registered with us. Providing witness statements and expert evidence in legal proceedings builds on Good medical practice to provide more detail on our expectations of medical professionals in this area.


The professional standards describe good practice, and not every departure from them will be considered serious. You must use your professional judgement to apply the standards to your day-to-day practice. If you do this, act in good faith and in the interests of patients, you will be able to explain and justify your decisions and actions. We say more about professional judgement, and how the professional standards relate to our fitness to practise processes, appraisal and revalidation, at the beginning of Good medical practice



Medical professionals play an important role in the justice system and other legal proceedings by providing factual, honest accounts of events and, objective and impartial advice if giving an expert opinion on matters within their competence and experience. 


The quality and reliability of witness evidence and expert medical opinion can make a significant difference to the fairness of the decisions and outcomes of proceedings. 


It’s clear from a number of high-profile court and tribunal cases that, where significant concerns arise about the quality of expert evidence, this may affect public confidence in expert opinion.1  It is essential that medical professionals acting as expert witnesses maintain high standards, given the potential for justice not to be correctly served. 


Expert Evidence in Criminal Proceedings in England and Wales by the Law Commission. Gross negligence manslaughter in healthcare – an independent report by Professor Sir Norman Williams.


More broadly, it’s important that, when asked to provide a witness statement or to act as an expert witness, medical professionals are clear about their legal and professional responsibilities, and have access to sources of advice and guidance to help them meet their obligations.2 


Medical experts in the family courts by the President of the Family Division. 


This guidance sets out the professional standards that apply to medical professionals who take on the responsibilities involved in giving evidence. It does not provide advice on the different UK legal frameworks and procedural rules that apply to witness statements and expert evidence, although it takes account of relevant legal requirements.      

The different roles


This is not a definitive list of roles, and the terms used to describe the role of a witness may vary. However, you might be asked to, for example:

  1. act as a witness of fact providing a witness statement (‘statement of fact’) about events where you work in which you’ve been directly or indirectly involved
  2. give expert opinion to the court, as the professional treating a patient – about the patient’s current medical condition and healthcare needs (this might be described as a ‘witness of fact’ or ‘professional witness’)
  3. act as an ‘expert witness’ – providing an independent, objective opinion on specialist or technical matters within your knowledge and competence. This might be in a court case considering the treatment options for a patient who is not in your care; in a clinical negligence claim; or a criminal case if you’re a forensic expert.

You will usually be required to provide evidence in a written statement of fact or an expert’s report, depending on your role. But you may then be required to give oral testimony about the issues covered in your written evidence. 

Ten key principles


These ten principles apply to all medical professionals – whether you are acting as a witness of fact (or professional witness) or proposing to act as an expert witness in legal proceedings.

12.1. You must act with integrity, honesty and objectivity, in whatever role you carry out in the legal process. 

12.2. You must take steps to understand the processes and timescales, your role, any procedural requirements you are expected to meet, and how to handle confidential information that you need to access or share as part of the process.

12.3. You must respond promptly to requests for your input. And take all practical steps to meet the agreed dates to provide statements or reports – and attend case conferences or preliminary case management hearings as required.

12.4. You must make sure any statement or report you write, or oral evidence you give, is accurate and not misleading. This means you must take reasonable steps to check the accuracy of the information you provide, and to make sure you include all relevant information.

12.5. Where it is possible to do so without misleading anyone, you should use language and terminology that people who are not medically trained will understand (including judges and jurors). You should explain any technical terms, and consider the use of visual aids, to meet the needs of the audience. 

12.6. You must only make statements, or give evidence and opinions on matters within your professional competence or where you have relevant knowledge. You must make clear what is factual evidence, and what is your opinion based on your professional judgement and experience. 

12.7. If a particular question or issue falls outside your area of expertise, or direct knowledge of events, you should explain this and decline to answer or comment. If, nevertheless in the circumstances, you are required to comment on the matter, you should answer to the best of your ability, but make clear the limits of your knowledge or competence.

12.8. You must not allow any personal or professional relationship with, or personal views that you might have about, individuals or organisations, to affect the objectivity or independence of any statement or evidence that you provide. 

12.9. Where you have a potential or actual conflict of interest, you must follow our guidance on Identifying and managing conflicts of interest, and any specific procedural requirements that apply in the circumstances (see paragraphs 24–25). 

12.10. You should consider any learning points from participation in the legal process as part of your reflective practice.4   


See information on ‘whole practice appraisal’ in Supporting information for appraisal and revalidation and the advice in Reflective practice.

Witness of fact: specific responsibilities


You may be asked to act as a witness of fact to provide a written statement, or give oral evidence at a hearing. 


You should limit your evidence to what you know, and wherever possible, it should be based on records and notes made at the relevant time. Depending on the case in which you’re involved, your evidence might include:

  1. your clinical findings, observations, and the resulting actions taken
  2. your reasons for making a particular decision or recommending a course of action 
  3. what you saw and heard at the time of the events in question.

You must follow the guidance in Confidentiality: good practice in handling patient information when you are deciding what information to disclose (starting with the general principles at paragraphs 8–10).


If you’re asked comment on or give an account of the actions and decisions of other people, as far as possible, this should be limited to matters which you have direct knowledge of. 


While they are not treated as ‘legal proceedings’ (in this guidance), you have a duty to  cooperate with reviews and investigations into serious patient safety incidents or events (Good medical practice 2024, paragraph 98 and Openness and honesty when things go wrong: the professional duty of candour guidance). If you’re asked to provide evidence or a statement about a patient safety incident, you should do so. These local processes are designed to support a learning and safety culture, and to avoid blame and punitive responses to adverse events and near-misses.5 


Information about national and local patient safety investigation programmes, and the processes involved, is available from bodies, such as Health Services Safety Investigations Body (HSSIB), Health Improvement Scotland (HIS),  the Maternity and Newborn Safety Investigations (MNSI), NHS Wales Delivery Unit, and the Regulation and Quality Improvement Authority (RQIA).


A statement that you make to assist in a patient safety investigation, serves a different purpose to a statement you might provide in response to legal action being taken by a patient (or other party) – in relation to an adverse event during the care of a patient. If you’re unsure about what needs to be included in any statement, you should seek advice from a more experienced colleague, your employer, defence body, or legal adviser.    

Expert witness: specific responsibilities


Expert medical opinions are sought from individuals who can give specialist or technical advice on matters where they have relevant competence, training, and experience. This might include professionals with:

  1. knowledge of the relevant standards and nature of clinical practice in a particular area of healthcare – at the time of the events which are the subject of legal proceedings 
  2. experience in a particular role, or in the care of patients with particular needs – where this is relevant to understanding the issues being examined or investigated
  3. technical expertise, such as forensic examination and interpretation of the findings.

If you wish to act as an expert witness in legal proceedings, you must have adequate knowledge of the current procedural requirements around providing expert reports and giving evidence, in the jurisdictions in which you intend to practise. This includes understanding the factors that the courts (or equivalent body) may apply in assessing:

  1. the suitability of an individual to act as an expert witness
  2. the admissibility and reliability of expert evidence. 

You should take part in relevant training to develop the practical knowledge and competencies required for the role, for example:

  1. familiarity with relevant guidance and codes of practice issued by professional bodies, such as the medical royal colleges, faculties, and specialist associations 
  2. understanding of how to write an expert report that meets the requirements of the court (or equivalent body)
  3. the practices around the joint instruction of experts by the parties to a case
  4. the procedures for attending and giving evidence in person or via remote connections
  5. effective presentation of oral evidence.

If you are asked to act as an expert witness, you must consider in each case whether you have the necessary knowledge, training, and experience to assist the court on the issues where expert input is required. You will be expected to outline your suitability to act as an expert, as part of any report that you provide.  


When providing evidence as an expert witness, you have a duty to the court which requires you to act independently and to be objective and impartial. This overrides any obligation you may have to the person instructing you or paying you to provide an expert opinion. 


You must make sure you understand what questions you are being asked to answer. If you’ve received instructions which are unclear, you must ask those instructing you to explain, so that you are in a better position to provide evidence that can assist the court. 


You must carefully consider, when asked to act as an expert witness and at all stages of the proceedings, whether you have a personal interest or any potential or actual conflict of interest that may affect or call into question your ability to give independent, objective evidence. For example, where you’ve been professionally or personally involved with any of the parties to a case. (See our guidance on Identifying and managing conflicts of interest).


You must make sure, without delay, that your instructing party is made aware of any personal interest, or potential conflict of interest. You may continue to act as an expert in the case, only if the instructing party provides written assurance that this is acceptable. 


An expert witness giving evidence within the justice system is usually able to consider all the available evidence (including statements and reports from the other parties to the proceedings), before forming and providing an opinion. If it is not clear whether you’ve been provided with all relevant evidence, you should check the position with those instructing you. Your instructing lawyer will be familiar with the disclosure requirements – for example, in preliminary case management hearings and the Scottish precognition process.


You must give an objective, unbiased opinion and be able to state the facts or assumptions on which it is based, including relevant clinical guidelines, or published research. If there’s a range of opinion on an issue, you must summarise the range of opinion and explain how you arrived at your own view. If you don’t have enough information on which to reach a conclusion on a particular point, or if your opinion is qualified (for example, because of conflicting evidence), you must make this clear.


If you are asked to give an opinion about a person without the opportunity to consult with or examine them, you must explain any limit that this places on your ability to give an opinion. If you decide to proceed, you should be able to justify your decision.


If at any stage you change your view on any relevant matter, you must make sure those instructing you are made aware of this without delay. It is then the responsibility of your instructing party to tell the other people who need to know, including the court if your expert report has already been disclosed to the court. 


You must respect the skills and contributions of other professionals who provide expert evidence, for example when preparing joint reports, while maintaining objectivity and impartiality in reaching your own view. If you have concerns about the competency or objectivity of another expert involved in the case, you should raise this with your instructing party who will consider what action it is appropriate to take in the circumstances.


If you are required to carry out interviews with or examinations of any of the parties involved in the case, you must make accurate notes, recording matters in a way that is not misleading or biased – for example, making sure you do not omit relevant information. A situation might arise where your examination identifies a risk to the person’s current health which they are not aware of, or a need to consider safeguarding action to protect them from harm. If this happens and you’re unsure what action is appropriate in the circumstances, you should seek advice from your instructing party or defence body.


You must follow our guidance on protecting confidential information from inappropriate disclosure. This means working in line with the general principles in Confidentiality: good practice in handling patient information (see paragraphs 8–10), and taking into account the guidance on disclosures which are ordered by the court – or necessary to comply with the procedural requirements involved in a particular case (Confidentiality: good practice in handling patient information, paragraphs 90–94). You must respect the requirement not to disclose information which is subject to legal privilege.6 


The term legal privilege refers to two types of protection from disclosure. Legal advice privilege protects communications between a lawyer and client as part of giving and receiving legal advice. Litigation privilege protects communications between lawyers, their clients, and any third party (including expert witnesses) as part of obtaining advice or information in connection with existing or contemplated future litigation. (Solicitor’s Regulatory Authority).


If there are situations within the legal process, where you are concerned about pressure on you to make inappropriate information disclosure, or that information may have been sent to you without the person’s consent, you should seek advice from your instructing lawyer or the court (or equivalent body).


You must make sure that you have appropriate and adequate insurance or indemnity that covers the full scope of your practice (Good medical practice, 101), and this includes any expert witness work. In addition, where you hold a licence to practise, your full scope of practice must be covered in your appraisals and the revalidation process.