Expert Witness work: Guidance for staff

We have created these notes as guidance for any researchers who are undertaking or thinking of undertaking any kind of expert witness work. The links in the section below are relevant to experts working on civil cases in the UK. However, we provide some additional links for criminal proceedings further down. You may be involved in a case outside of the UK where different rules apply, and the lawyers instructing you should direct you to the relevant regulations and guidance.

Points to consider

  • Understand what commitment is expected of you: initially, you are likely to be approached to provide your opinion on the case in the form of a report. However, it is usually expected that you would be prepared to act as an expert witness and testify if the case goes to court, even if proceedings have not yet begun. It can be difficult to determine what kind of time commitment is likely to be required from you, and trials can be lengthy. It can take several years for cases to come to court so this may be a long-term commitment. Giving evidence in court and being subject to cross-examination can be quite an intimidating experience, but the instructing lawyers should help you to prepare for this.
  • Understand your role: Your role is to provide an independent, unbiased, and objective opinion on the case based on your professional knowledge and experience, and all material facts that you are provided with. Only provide opinions on matters which lie within your expertise, and highlight any areas which might fall outside your expertise. The lawyers instructing you are responsible for satisfying themselves as to your qualifications and experience however, it is still important that you provide a full, unambiguous, up-to-date CV and a clear indication as to whether you are experienced in this kind of work. OUI will set up a contract with the specific terms of your appointment, and your role will be set out in more detail in the ‘Instructions’ (see section below “What lawyer’s instructions should include?”).
  • Understand your legal responsibilities: You have a duty to exercise reasonable skill and care to the party instructing you. However, you have an overriding duty to the court in assisting them to reach a reasonable and considered determination. You should ensure that you are familiar with the Civil Procedure Rules 35 and the Practice Direction. The Civil Justice Council have produced guidance notes for the instruction of experts in civil claims and interpretation of CPR35. This contains guidance on accepting instructions, writing and amending reports, discussions with other expert witnesses and attending court.
  • Understand your conflicts of interest: the lawyers instructing you will want to establish early on if you have any conflicts of interest in relation to any of the parties involved in the case. You must disclose any possible conflicts, which could include you having research collaborations with or consulting for one of the parties involved. You will be expected to agree that you will not advise on other legal matters or proceedings which are in the same subject area and could have an adverse effect on the client instructing you.
  • Understand the risks: In March 2011, the Supreme Court abolished expert witnesses’ immunity from suit for breach of duty. If you arrange your expert witness consultancy through OUI, you will be covered by the University’s Professional Indemnity insurance. Experts should also be aware that sanctions might apply as a result of failure to comply with CPR 35, the PD or court orders, as set out in the CJC Guidance.

What lawyer’s instructions should include?

The lawyers instructing you should provide you with a clear and detailed set of instructions which should cover:

  • Basic information about the claim and all parties involved
  • Nature of expertise required, purpose of advice or report and description of matters to be investigated
  • Documents relevant to advice or report
  • Whether proceedings have started or are contemplated and whether they are seeking just advice or a commitment to act as an expert witness
  • Outline programme for the delivery of each stage of work, dates of any hearings, dates for exchange of expert reports, and other relevant deadlines
  • Specific budgets

You are expected to confirm without delay if the instructions are acceptable, or let the instructing lawyers know of any aspects which aren’t acceptable.


Report icon Report

Reports should always be objective, impartial and clearly state all facts and assumptions on which your opinion is based. Further information can be found in the CJC Guidance. Bond Solon have also created a model template for reports.

Your report should list all of the information you have been given in relation to the case, including any you haven’t used. Your report should be addressed to a non-expert in the subject matter; try to pitch it at the level of a promising A-level student.


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Giving evidence in court icon Giving evidence in court

Most cases will not end up going to court, but if you are called to testify then the instructing lawyers should help to prepare you for this. It is important not to come across as being ‘unchallengeable’; answer questions thoughtfully, consider other views that are put forward and be prepared to concede on anything you’re not certain of.

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Healthcare professionals (HCPs) acting as expert witnesses icon Healthcare professionals (HCPs) acting as expert witnesses

Expert witness work in criminal proceedings icon Expert witness work in criminal proceedings

Experts involved in criminal proceedings should be directed to:

(i) Part 19 of the Criminal Procedure Rules (

(ii) CPS Guidance for Experts on Disclosure, Unused Material and Case Management (

(iii) Criminal Practice Direction 19, A, B, C

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