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Disclosure Manual: Chapter 23 - Disclosure of Unused Forensic Science Material

Refreshed: 21 October 2021|Legal Guidance

This chapter provides guidance on how unused material in the possession or control of a forensic science provider (FSP) should be revealed to the police and then to the prosecutor. It also reflects the agreement reached between the CPS, the National Police Chiefs' Council (NPCC), and the FSPs as to the best way to comply with the legal duties of disclosure to the defence imposed under the CPIA.

Police and prosecutors should apply the instructions in this chapter in conjunction with the general instructions contained in this manual, which continue to apply, and Part 19 of the Criminal Procedure Rules ('Expert Evidence'). FSPs should incorporate the guidance into their quality management systems.

The common law duty

Where the Common Law applies, 'the prosecution team' will include the prosecutor, investigator and any expert witness instructed by the prosecutor or the investigator e.g. forensic scientists, psychiatrists, pathologists, police surgeons. All must reveal the existence of all unused material to the prosecutor and the prosecutor will then decide whether it needs to be disclosed to the accused.

It should be noted that the case of R v Ward [1993] 1 WLR 619 placed a further important duty upon the expert, as follows:

"… an expert witness who has carried out or knows of experiments or tests which tend to cast doubt upon the opinion he is expressing is under a clear obligation to bring records of those tests to the attention of the solicitor instructing him …"

The experiment or test material should be supplied to the disclosure officer and prosecutor.

Duties under the CPIA

The CPIA Code of Practice does not apply to forensic scientists and other experts, although any material or information that they supply to or retain on behalf of the police will be subject to CPIA duties.

Unused material retained by forensic science organisations and not copied to the police can only be acquired by the defence through the witness summons procedures (see Chapter 4) unless the information is volunteered.

Preservation of material

Whilst the CPIA and its Code of Practice do not impose any specific duties upon forensic experts themselves regarding the preservation of material, it is vitally important that all material or information which may be relevant to the investigation and to the outcome of the case is recorded and retained. Para 5.4 of the Code sets out categories of information over which there is a particular duty to retain which specifically includes “communications between the police and experts such as forensic scientists, reports of work carried out by experts, and schedules of scientific material prepared by the expert for the investigator, for the purposes of criminal proceedings”.

When expert opinion is sought from the FSP not all the circumstances may be known. It would therefore be unwise to speculate on what the defence might be when deciding what to record or what to keep.

In particular, the FSP should always record the following:

  • the results of any tests or calculations, whether positive or negative;
  • any information obtained in connection with the forensic examination whether this points towards or away from the suspect; and
  • any information generated during the course of the examination that might have some bearing on any offence under investigation or any person being investigated.

Notes and records of the above should always be retained by the FSP, together with the following items in particular:

  • notes and draft versions of reports or witness statements (especially where these differ from the final version); and
  • any material gathered or generated in connection with the forensic examination, subject to specific arrangements to return material to the police following examination or to destroy it.

If there is any doubt as to whether material should be retained, or whether information should be recorded, discretion should be exercised in favour of preservation, recording, and retaining.

Procedures: general

The FSP should inform the police of all material retained in their possession in accordance with the procedure set out below.

FSP actions: preparation of the index

The FSP should provide to the police an index of all material in their possession. The scientific reporting officer should prepare the index and submit this to the police investigator when the report or statement is supplied under CrimPR 19.3(3) in all cases except where an analyst's certificate is supplied in drink-drive cases.

All material should be individually listed on the index and described clearly and accurately so as to allow an informed decision on disclosure. Where there are many documents or items of a similar type or repetitive nature, these may be described by quantity and a generic title but as with police schedules may be returned if there is insufficient information. However, any single item which is known to be of particular significance should be separately listed.

If not mentioned in the report or statement, the reporting officer should indicate on the index any material that satisfies the disclosure test, so far as this can be assessed or is known. Wherever practicable, copies of material that satisfies the test should be sent to the police with the index.

The disclosure officer's duty of revelation to the prosecutor and the prosecutor's duty of disclosure to the defence are continuing obligations. Therefore, the index must be kept up to date by the FSP. Where new material comes to light or is generated or received after the initial preparation and submission of the index, a supplementary index should be supplied to the police.

Police actions: dealing with the forensic index

Where a police officer receives an index from the FSP, this must be retained, together with any other report, statement or document supplied. Any relevant oral information received by the investigator, or by the disclosure officer relating to material held by the FSP should be recorded and retained in accordance with the CPIA Code of Practice.

Upon receipt of the expert’s index of unused material, the disclosure officer should check the material listed on the forensic index. The index should list all material retained in the possession of the FSP. The disclosure officer should list the index itself on the schedule of unused material simply saying for example Expert’s Index of Unused Material – compiled on xxx – list of all material in possession of expert/forensic science provider'.

Where the disclosure officer believes that any of the material appearing on the index, satisfies the disclosure test the item should be listed on form MG6E or SDC. The disclosure officer should consult the reporting officer where he or she is in any doubt. If any FSP derived material could cast doubt on the reliability of a witness, it would fall within the specified categories of material to which the rebuttable presumption applies (see above).

The schedules, the index and any undermining or assisting material should be sent to the CPS with the file in the usual way.

Where the prosecutor indicates that unused material in the possession of the FSP requires disclosure, the disclosure officer should send a copy of the index endorsed with the prosecutor's decision to the FSP.

CPS Actions: disclosure to the defence

Upon receipt of the index, the prosecutor should review the listed items in the same way as other unused material. The FSP should be notified of the prosecutor's disclosure decisions via the disclosure officer.

Upon receipt of a defence statement, the prosecutor should exercise the continuing duty of review under the usual principles.

Police actions: defence statements

When a defence statement is received, or where information comes to light from any source which might have a bearing on or otherwise affect any evidence supplied by a forensic expert, the disclosure officer should consider, in consultation with the investigator and the prosecutor, whether further enquiries need to be made.

The disclosure officer should send a copy of the defence statement to the forensic scientist together with instructions as to any further report or work required. A date should be given as to when a response is required. Situations where this should occur will include:

  • where forensic evidence is challenged directly;
  • where issues raised in the defence statement may have a bearing on the interpretation of scientific evidence;
  • where the scenario put forward by the defence statement differs significantly from that upon which expert opinion is based; and
  • whenever it is necessary to ask the FSP to review the forensic material or to conduct further tests in order to clarify the issues raised by the defence statement;
  • where any issue is raised that might have a bearing on forensic material, either used or unused, and;
  • where a new line of enquiry is indicated, and the officer in the case considers that it should be pursued.

Where the disclosure officer is not clear whether the defence statement has any bearing upon forensic material, the FSP should be contacted for advice on whether it may be desirable to review the material in the light of the defence statement.

In appropriate circumstances, it may be desirable to arrange consultation between the police investigators, the forensic scientist, and the prosecutor to decide upon a suitable course of action. Whatever the nature of the case, it is important to maintain appropriate liaison between the FSP, the police and the CPS to ensure that the disclosure process is completed properly and clearly recorded. The prosecutor should ensure the DRS is updated.

CPS actions: defence requests for FSP material

Any requests received by the CPS for disclosure of unused material in the sole possession of FSP should be the subject of consultation between the prosecutor and the disclosure officer. Consideration should be given to obtaining the material.

If, following such a request and consultation, the prosecutor decides not to seek access to the material, the defence should be asked to refer their request directly to the FSP concerned who will decide whether they will provide voluntary access.

FSP actions: access arrangements for the defence

The FSP is a third party under the CPIA. The defence might make a direct approach to the FSP for access to case material, informally or by way of witness summons. The FSP will notify the police of such approaches. The FSP has discretion to allow voluntary access but must comply strictly with the terms of any witness summons.

Whenever access is sought by the defence to used or unused material, the FSP will:

  • notify the police of any requests by the defence for access, and of any arrangements made;
  • advise the police where the defence seek to carry out further tests which may alter, damage, or destroy the material;
  • make arrangements for ensuring that the integrity of exhibits is maintained and a continuity record is made where these are subject to defence examination;
  • keep a record of any defence examination, including the nature and extent of the examination, and any views expressed; and
  • notify the police if the forensic scientist's views are likely to change as a result of the defence examination.

Where the prosecutor has indicated that unused material in the possession of the FSP should be disclosed, the disclosure officer will send a copy of the index, MG6C or SDC, and any letter to the defence to the forensic scientist so he/she is aware.

On production of a copy of the MG6C or SDC schedule or index (or covering letter, if the latter refers to the material directly) marked with a 'D' or 'I' by the prosecutor, the FSP should allow access. The FSP will use the copy MG6C or SDC supplied by the police as a checklist, and to identify material that does not require disclosure at that time.

Supervision of access to non-sensitive unused material by the FSP will be governed by way of local arrangements. Best practice suggests that the investigator or disclosure officer is present wherever possible when the defence examine any forensic material.

It should be noted that the defence may also be entitled to access to material in the possession of forensic science organisations through the operation of Part 19 of the CrimPR. This will relate to the records of any tests, calculations, documents, or objects upon which the forensic scientist bases his expert opinion and which forms part of the prosecution case.

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