The report

Types of report

1. There are likely to be two main types of expert report in prosecution proceedings:

  • one dealing with clearly measurable matters (such as the results of analysis and tests);
  • the other with broader matters of opinion, such as safe systems of work.

2. The first can best be described as a laboratory report and the second might be termed a consultant's report, although some reports may include elements of both.

3. In certain circumstances, particularly where advice is sought but prosecution is not envisaged, specialist inspectors might prepare a short summary report. However, where an investigation is likely to lead to enforcement action, a more detailed report and, where necessary, a formal witness statement will be required. Experts may either produce a full report, exhibited in a brief covering statement on an LP70 form (see 'Exhibiting the report' below) or, if the information is shorter (such as a laboratory report), they may provide all the information in the statement itself, on form LP70. Whilst both approaches are valid, it is recommended that specialists draft reports in such a way as to allow them to be formally exhibited to a statement if required; this will also make it easier to update the report if further information is received.

4. Reports should ideally therefore be stand-alone documents. See later regarding the importance of preparing draft reports until the report can be finalised.

Contents of the report 1

5. All reports should begin with the expert's name, official address, occupation, relevant academic and professional qualifications, accreditations including membership of professional institutions, career history, relevant experience, the range and extent of his/her expertise and any limitations upon the expertise. There is an option to include a detailed CV in an appendix.

6. The report should also include:

  • A statement setting out the substance of all the instructions received (written or oral), questions upon which an opinion is sought, the materials provided and considered, and the substance of all facts, documents, statements, evidence, information or assumptions which are material to the opinions expressed or upon which those opinions are based. The expert should make clear which of the facts stated in the report are within the expert's own knowledge;
  • Where necessary, the report should give the current state of the inquiry and the areas where further information would be needed to reach a final view. If the expert is not able to give an opinion without qualification, s/he should state the qualification;
  • Information on who has carried out any examination, measurement, test or experiment which the expert has used for the report, including that person's qualifications, relevant experience and accreditation. The report should give details of the methodology used, summarise the findings on which the expert relies and say whether or not such measurements etc were carried out under the expert's supervision;
  • Where there is a range of opinion in the matters dealt with in the report, a summary of the range of opinion and the reasons for their opinion;
  • If the expert is not able to give an opinion without qualification, state the qualification;
  • Include such information as the court may need to decide whether the expert's opinion is sufficiently reliable to be admissible as evidence; For example, any material facts or matters that detract from the expert's opinions, and any points which should fairly be made against any opinions expressed in the report, should also be set out; See paragraph 33A.5 of the Criminal Practice Direction V for examples of factors the court may take into account when deciding reliability
  • Details of any literature or any other information or material which the expert has relied on in making the report or which might assist the court (see also 'Extrinsic material' below);
  • A summary of the conclusions reached;
  • A statement that the expert understands their duty to the court to provide independent assistance by way of objective and unbiased opinion on matters within their expertise and that they have complied, and will continue to comply, with that duty. The expert should acknowledge that the expert will inform all parties and, where appropriate, the court in the event that their opinion changes on any material issue;
  • The same declaration of truth as that contained in a voluntary witness statement form (LP70).

7. The statement and declaration required by (ix) and (x) above should be worded substantially the same as the wording provided by paragraph 19B of CPD 2015 Amendment No. 2 (see Appendix 1 for wording)

8. The expert's final opinion should be based on as much information as possible and if necessary they can then deal with any question which may arise subsequently, including matters which counsel may wish to be dealt with if the case goes to the Crown Court. The report should not be signed by the expert until it is ready to be disclosed. For guidance on draft reports, see below.

9. Expert evidence may be introduced by way of summary (if the other party agrees) or by serving the report on the court and the defendant/s as soon as practicable and in any event, when the prosecution is making an application which is supported by the expert evidence, for example at mode of trial. 2

10. If service is not carried out in accordance with the Criminal Procedure Rules, the expert evidence cannot be introduced, unless all parties agree or the court gives permission. 3

11. When an expert report is served on another party or the court, those instructing the expert must inform them at once 4. If, on exchange of experts' reports, matters arise that require a further or supplemental report, the above guidelines should once again be followed.


12. The opinion of an expert is admissible on matters that are outside the ordinary knowledge of the court 5 but within their expertise. The expert should therefore make it clear when any matter falls outside their expertise.

13. If more than one expert is to be called by the prosecution, it is important to avoid too much overlap in their reports. Each expert should indicate where their expertise ends and should not go 'out on a limb', as they will be cross-examined on the report if the case is defended.

14. The prosecution must establish its case beyond reasonable doubt, but it can still do so despite a doubt which an expert might have to accept. This has been expressed as follows 6:

  • the available data may be inadequate to prove scientifically that the alternative hypothesis is false, so the scientific witness will answer "No, I cannot exclude it," though the effect of his evidence as a whole can be expressed in terms such as "But for all practical purposes (including the jury's) it is so unlikely that it can safely be ignored".

15. The expert should explain the operation and any shortcomings in terms which a layman can understand, and it may be useful for them to use headings.

16. If the expert has dealt with similar subject matter elsewhere where better standards were achieved, they can make comparisons.

17. The expert should not, disregard evidence or conclusions that are unfavourable to the prosecution. They should deal with factors that do not support their opinion and explain how they have taken them into account. These should be discussed with the Investigating Inspector, and / or lawyer and the expert should point out any potential problems.

Expected defences

18. The expert should be asked to deal with any expected defence and evaluate any defence documents. Although the prosecution expert will give evidence first, their report can be the basis for advance rebuttal of expected defences.

  • Medical confidentiality

19. The relationship of doctor and patient is one to which a duty of confidentiality attaches in order to ensure that patients make full and frank disclosure when seeking diagnosis and treatment. A patient has a right to expect that their doctor will not pass on any personal information which they acquire in the course of their professional duties, unless the patient gives consent. However, this duty of confidentiality is not unlimited.

20. Irrespective of consent, disclosure may be necessary in the public interest when failure to disclose may expose the patient or others to risk of serious harm. In such circumstances, the doctor must disclose the information promptly to an appropriate person or authority 7. Disclosure is also justified for the detection and prevention of serious crime, to satisfy a statutory requirement, or following an order of the court.

21. General Medical Council (GMC) guidance entitled 'Confidentiality"(2009) confirms that disclosure must be made to satisfy a specific statutory requirement, for example, notification of a known or suspected case of certain infectious diseases (paragraph 17 of the GMC guidance) or on the direction of a court. The guidance also states that only so much of the patient's (or deceased person's) notes and records as is relevant should be disclosed (paragraph 21).

Exhibiting the report

22. To exhibit the report to a witness statement (form LP70), the initials of the author and a consecutive number should be used (see Preparing evidence for court for guidance on exhibits). To formally exhibit the report, the usual form of words in the witness statement is as follows:

  • "I produce a report of my findings [X pages long] as exhibit YZ/1 [initials of the author and the report followed by a number: this will always be '1' unless the expert has already produced exhibits in their LP70 statement], which is signed by me and dated [date of signature]".

23. When a witness (including an expert) signs a statement on form LP70, they sign a declaration that states that the content of the statement is true to the best of their knowledge. The witness also accepts that they might be prosecuted if they knowingly state something which they know to be untrue. The responsibility for the final content of the report remains with the author.


24. The expert should exhibit any presentational material that they have produced, and they may refer to exhibits produced by others, such as photographs, sketches, models, plans, tables and graphs. Even in the simplest of cases, illustrative material may be very helpful in explaining the case to the court.

Extrinsic material

25. The expert should bring to the attention of the prosecutor and the court any material that will help decide the case. This may include articles, published papers, codes of practice, guidance, published and unpublished research reports etc. References to material to which the defendant would or should have had access may be particularly useful.

26. Courts have taken account of official publications in a number of reported cases 8 and an employer is under a duty to keep abreast of developing knowledge 9. Some material may be illustrative and some may set standards either for analysis or safety.

27. The expert should exhibit to the report any material to which they refer, or the relevant extract from it, and they should have the whole document or publication available in court.

28. Some documents may be produced without being exhibited to the report (for example, approved codes of practice 10) but in some cases it may be necessary for the expert to explain its significance . Regulations may also require explanation.

29. The expert may need to do a literature search or obtain a statistical analysis, and if they can verify that analysis, it will not be necessary to call the statistician 11. They may use material stored in a computer; for guidance on the admissibility of such evidence, see the sections Preparing evidence for court - computer records and Computer evidence.

30. The defence may object to reference to other documents (of which the expert is not the author) on the grounds of hearsay. Examples of such documents include British/EN standards, HSE guidance notes, industry publications, calculation tables 12, textbooks, articles and summaries of research 13. The prosecutor must establish that the expert is competent to express an opinion on such material; where it does form part of the expert's body of expertise, the expert may refer to the material in order to support their opinion without infringing the rules against hearsay 14.

Updating the report

31. As indicated in 'Contents of the report' above, after an expert report has been produced, matters may arise that require the report to be amended. Consideration should be given as to whether a new, revised report is necessary or whether, if the changes are only minor, additional information could be produced in the form of a supplementary report. Details of the changes, referring to the sources of any new or additional information and setting out any revised conclusions, must be recorded. Supplemental Reports must contain the statement and declaration required by paragraph 19B of CPD 2015 Amendment No. 2 (see Appendix 1 for wording).

Draft reports

32. The report, or statement, of an expert should not be signed at an early stage; it should initially be considered a draft and marked as such. This is because:

  • the expert will not necessarily have seen all the evidence;
  • the expert may consider on reflection that the case, or a part of it, is outside their expertise; and
  • the informations/charges and the ambit of the investigation may not yet have been finalised.

33. Draft reports and statements should be retained, as they may be disclosable to the defence (see below). Whether draft reports will in fact be disclosed at a later stage will be a matter for the disclosure officer and prosecutor, who consider the disclosure test.


34. As indicated above, experts must have read the guidance booklet: Disclosure: Experts' Evidence, Case Management and Unused Material and provide a declaration within their report stating they have done so and that they have:

  • complied with their duties in accordance with the Criminal Procedure and Investigations Acts 1996, and,
  • provided a list of all relevant material (that they have gathered or generated).

35. All relevant material held by an expert in relation to an investigation should be listed by the expert, and a copy of the list provided to the inspector. The inspector should ask the expert for this list which should then be passed to the disclosure officer to decide whether the items on the list need to be entered on to the disclosure schedules.

Laboratory reports

36. As with any other expert report, these should be either in the form of a statement or in a report exhibited by a statement, both of which can be used in evidence without the need for the expert to attend court. The Laboratory report (regardless of the format used) must include the statement and declaration required by CrimPR 19.4 and should be worded substantially the same as the wording provided by paragraph 19B of CPD 2015 Amendment No. 2 (see appendix 1 on 'The Expert' page).

37. The statement should be given on form LP70 and typed (double-spaced). If the report/statement deals only with matters which are strictly measurable, and there is no likelihood of it being challenged or requiring further elucidation, the expert should sign it. Laboratory reports can often be agreed.

38. The expert should refer to the section 'Contents of the report' above and ensure that their involvement in the tests is clearly stated. For example, they should either say: "The tests were carried out by me" or "The tests were carried out in my presence and under my direct personal supervision".

Standards, conduct and consultation

39. The specialist will need to:

  • agree with the investigating inspector the nature of the science, technology or medical support required;
  • maintain a communication record; and
  • retain all information relating to the incident and make it available to the investigating officer/disclosure officer on request.

40. Consultation with colleagues, including the line manager, can provide the specialist/expert with an opportunity to:

  • develop and explore opinions on the issues involved;
  • identify other areas for consideration;
  • examine the foundation of any assertions reported;
  • ensure appropriate team working; and
  • inform future action.

41. Professional oversight of a specialist's work by their line manager is useful in establishing a benchmark for quality and accuracy and can be done without compromising personal authorship of the report.

42. Discussion of the content of a report between the specialist and the inspector or lawyer/s is entirely proper, provided care is taken to ensure that the report is, and is seen to be, the expert's own product 15. When an inspector, or anyone else, communicates with an expert, whether in-house or from outside, they should be careful to ensure that there is no risk that the communication could be misinterpreted so as to suggest that it might influence the expert's opinion.

43. Both the specialist / expert and the inspector (or other person) instructing them should remember that all communications (including draft reports), other than those between an expert and lawyers, may be liable to be disclosed. Communications between the expert and the lawyers in the case are privileged 16. A note of any such discussion should be made and retained.

44. The expert should set out in their report only those facts that have been, or are to be, proved in evidence and other expert opinion upon which they base their opinion. They can refer to written admissions made by the defendant. Experts should be aware that, just as a party must challenge in cross-examination contested evidence given by a witness of fact, so the opinions of an expert must be challenged if they are disputed.

45. Before any decision to prosecute is taken, it is permissible for an expert to advise as to whether, in their opinion, there is any breach of the law; the balance of legal opinion permits an expert to give opinion on what has been called "the ultimate issue". However, experts should be careful; where an expert deals with such an issue in their report, the judge in a Crown Court trial must direct the jury that they are not bound by the expert's opinion, and that the issue is for them to decide 17.

46. The defence must serve its expert evidence on the prosecution as soon as practicable and in any event if the defence is making an application which is supported by the expert evidence 18. The prosecution expert should see this evidence and provide comments for counsel, who may ask them to prepare a further report dealing with the defence evidence.

47. There is no restriction on an expert meeting counsel; before going into court, an expert is entitled to discuss with counsel (or legal representative) the relevant points that will bring out the essence of the case. Counsel must not, however, rehearse, practise or coach any witness, including experts 19.

48. An expert should consider the lines of argument that the defence may put forward. In a covering minute (rather than the report), the expert should deal with:

  • any defences which are possible but unlikely;
  • matters which the expert may deal with in a certain way if they arise; and
  • any suggestions for further expert evidence.

49. An expert may also prepare notes for the prosecutor to use when cross-examining.

50. Historically, an expert had immunity from any proceedings against them for liability arising out of their expert evidence. This position is no longer true. An expert is now liable to the person or body who instructs them for the evidence given. So, for example, a client can sue an expert for any loss suffered as a result of any negligence in that expert's evidence 20. However, although this applies to experts in criminal proceedings, HSE specialist inspectors are unlikely to find themselves in this position as such matters could be dealt with through internal disciplinary procedures and/or referral to the relevant professional body, as appropriate. Section 26 of HSWA provides an indemnity for inspectors.

51. The above exemptions relate to evidence given in court. In the preparation of their evidence, and in their conduct before and during the proceedings whilst outside the witness box, witnesses instructed by or on behalf of HSE are expected to act professionally and in line with their contract of employment or instructions. Experts must have read and adhere to the guidance booklet: Disclosure: Experts' Evidence, Case Management and Unused Material. Additional guidance on disclosure is set out here and in the section 'Approach to common categories of material' in [Expert and Specialist].

52. Expert witnesses may be the subject of management control and/or auditing to ensure quality and accuracy. Experts can legitimately be asked to account for any delay caused in providing their written opinions and may be required to do so in open court.


  1. Rule 19.4 Criminal Procedure Rules ('CPR'). Also, the Court of Appeal gave guidance on the matters to be included in an expert report in criminal proceedings in R v B [2006] EWCA Crim 417. Back to reference of footnote 1
  2. Rule 19.3(1)-(3) CPR. Back to reference of footnote 2
  3. Rule 19.3(4)CPR. Back to reference of footnote 3
  4. Rule 19.5 CPR. Back to reference of footnote 4
  5. R v Turner [1975] 60 Cr. App. R. 80, CA. For example, in Wood v DPP [1989] 153 JP 20, a doctor's "opinion" was not admissible as it was held to be within the magistrates' own experience. Back to reference of footnote 5
  6. R v Bracewell [1979] Crim. LR 111 CA. Back to reference of footnote 6
  7. W v Egdell [1990] Ch 359; R v Cozier [1991] Crim LR 138, CA. Back to reference of footnote 7
  8. Dickson v Flack [1953] 2 All ER 840; Mitchell v North British Rubber Co. [1945] JC 69; Harrison v Metropolitan-Vickers Electrical Co. Ltd [1954] 1 All ER 404. Back to reference of footnote 8
  9. Stokes v GKN [1968] 1 WLR 1776. Back to reference of footnote 9
  10. Codes of Practice approved under HSWA s.16 are admissible by virtue of s.17 if relevant. Although the standard introduction to Codes says that failure may be used in criminal proceedings as evidence that a person has contravened a Regulation, it should be noted that the matter to which they relate "shall be taken as proved unless" etc. "May" relates to the discretion whether to prosecute. Back to reference of footnote 10
  11. Stone and Sons v Pugh [1949] 1 KB 240. Back to reference of footnote 11
  12. R v Somers [1963] 3 All ER 808 CA: evidence of the destruction rate of alcohol in the blood. R v Abadom [1983] 1 All ER 364: evidence of tables giving the refractive index of glass. Back to reference of footnote 12
  13. H v Schering Chemicals Ltd [1983] 1 All ER 849: summaries of research, articles and letters in medical journals, etc. relevant to personal injuries caused by a drug. Back to reference of footnote 13
  14. R v Abadom [1983] 1 All ER 364: English Exporters (London) Ltd. v Eldonwall Ltd [1973] Ch 415. Back to reference of footnote 14
  15. Whitehouse v Jordan [1981] 1 WLR 246 HL at 256. Back to reference of footnote 15
  16. Harmony Shipping Co. v Davis [1979] 3 All ER 177. Back to reference of footnote 16
  17. 17. R v Stockwell 97 sCr. App. R 260 CA, R v Gokal [1999] 6 Archbold News 2 CA and see Archbold 2015 edition at paragraph 10-51. Back to reference of footnote 17
  18. The Criminal Procedure Rules, Rule 19.3(3). Back to reference of footnote 18
  19. You should bear in mind that even a covering minute may have to be disclosed. Back to reference of footnote 19
  20. Jones v Kaney [2011] UKSC 13. Back to reference of footnote 20

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Updated 2023-11-13