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Disclosure Manual: Chapter 32 - Co-ordination of Disclosure Issues involving Multiple Police Force and Multiple Agency Investigations Within the UK

Refreshed: 21 October 2021|Legal Guidance


Where enquiries reveal the existence of a separate but linked investigation(s) conducted by another force or agency, a formal agreement between the forces/agencies concerned should set out their respective roles and responsibilities.

Investigations may be linked by, for example:

  • the suspect(s) being the same;
  • surveillance by different agencies uncovering related suspects;
  • suspects becoming related after the commencement of an investigation by virtue of being accessories or accomplices; or
  • where one investigating agency supplies assistance or information to another investigating agency.

This guidance provides for two types of agreement:

  • an NCA operational memorandum of understanding (OMOU) where investigators wish to establish a long-term case relationship; and
  • a disclosure agreement document (the 'disclosure agreement') for cases involving other investigators and where more limited assistance is provided in an NCA case.

The operational memorandum of understanding (OMOU)

The purpose of such an agreement is to agree the strategic and tactical objectives of the operation, and the roles and responsibilities of the parties, including those relating to disclosure so that each party is aware of its specific responsibilities.

In an NCA operation, the prosecutor should be notified and a copy provided at the earliest opportunity. The prosecuting agency should be made aware of any changes to the document as they are made.


The prosecutor should be fully engaged in the disclosure process from an early stage. Where relevant, respective agencies' prosecutors should have regard to the Prosecutors' Convention in order to coordinate revelation and disclosure, and consider inter alia how to co-ordinate related prosecutions, lead prosecution responsibility, timing of proceedings, mechanisms for sharing information and other disclosure issues.

Linked investigations

When a link between different investigations is discovered, the respective officers in charge of the investigation should discuss the nature and extent of the link to assess whether the used and unused evidence of one investigation might impact directly upon or be relevant to the other investigation.

Coordination of disclosure issues should be evidenced within the disclosure agreement, together with the nature and extent of any future relationship. The extent of the link and the subsequent relationship desired will vary. Depending on the relevance of material to the particular prosecution, it may also be appropriate to document the strategy and disclosure decisions relating to linked investigations in the DMD.

Police investigations can cross force boundaries, or a National Crime Agency enquiry may lead to the adoption of a local force's investigation. Where the NCA is involved, an OMOU should be agreed.

Each force is bound by the CPIA Code of Practice and the AG Guidelines and has duties to record and retain relevant information and material and reveal relevant material to the prosecutor. The officer in charge of the investigation in each agency should appoint the disclosure officer and decide the number and location of deputy disclosure officers, bearing in mind the volume and the geographical location of the material. This should be recorded and the agreement should be kept updated by the respective officers in charge.

The lead disclosure officer is responsible for:

  • overall disclosure strategy (and should involve the prosecutor at the earliest possible opportunity) and being the central point of contact;
  • assessing the disclosure implications of any other linked investigations, and;
  • facilitating the free flow of information between investigators, paying particular attention to areas, which may satisfy the disclosure test. To assist this process, a disclosure conference with all the deputy disclosure officers is recommended. This should be followed by regular briefings.

Investigators should prepare a summary of the main points for each offence to assist the disclosure officers. Regular meetings of the disclosure officers on each enquiry should support this process and they should attend the joint briefings and all conferences, as necessary, to keep fully abreast of developments. Disclosure officers have a continuing duty to assess material generated by the investigation and during the course of the trial.

In particularly sensitive enquiries, it may be necessary to appoint deputy disclosure officers for different topics, for example, one disclosure officer for the main investigation and another for the highly sensitive material. These officers must work closely together and be aware of all aspects of the case.

Obtaining material from government departments

The Guidelines make it clear that where it appears to an investigator that another government department or agency may have relevant material, they must take reasonable steps to identify and consider it.

Under the Act and the Guidelines, government agencies, departments or Crown Servants are normally considered third parties in relation to an investigation carried out by a different investigative agency. One government agency cannot be deemed to be in constructive possession of material held by another government agency (see para 35). However, unlike other third parties, such agencies or departments have a public law duty to cooperate with a criminal investigation. Moreover, the Human Rights Act 1998 makes it unlawful for public authorities to act in a way that is incompatible with a convention right, which includes the right to a fair trial guaranteed by Article 6.

In some circumstances, there may be a statutory prohibition in relation to disclosure of information to those outside the department and it will be necessary to gain access through that department or agency's statutory gateway to allow the disclosure of information.

Where there are parallel or linked investigations between agencies, both agencies may be investigators under the CPIA with the resulting duties to record and retain. However, the fact that one agency may have simply been tasked to assist another investigating agency may not of itself be enough to make it an 'investigator', with the related duties to record and retain. Whilst it will always be a matter of fact and degree, the status of any tasked agency should be agreed at the earliest possible opportunity and recorded in the OMOU or disclosure agreement as appropriate to avoid potential confusion and uncertainty.

For the procedure for obtaining highly sensitive material gathered and/or generated by the security and intelligence agencies, see the relevant restricted chapters.


Any issues in relation to the handling of sensitive material and/or its security should be set out within the OMOU or formal agreement, as information will not be shared unless the appropriate level of individual clearance is observed and secure storage is available. In relation to the security of the material itself, each department or agency will have security advisors. Material should always be dealt with according to its security classification.

Sensitive material and PII hearings

Material may be considered sensitive or highly sensitive by one agency but that view may not be shared by another agency. It is important that there is clear communication about such matters and if necessary, areas of dispute are escalated as appropriate.

The prosecutor should consider the possible need for a PII application at the earliest stage and record their views in line with Chapter 13 of this manual. The views of the owner of the material, if they are a separate agency, should also be sought and the owner should be given the opportunity to make representations to the prosecutor prior to the hearing and be separately represented at, and/or attend the hearing.

Where another agency or department wishes to have its own representation at court, the prosecution advocate should assist where possible by setting out the agency's interest in the case to the judge.

All investigators and prosecutors should refer to guidance on PII applications, scheduling, and CHIS issues in this manual.


A number of law enforcement agencies adhere to a system of flagging for subjects under investigation and provide checks against their data on behalf of other law enforcement agencies. The principle of flagging is that if an investigator has an interest in an individual, through investigating an offence or commencing an investigation or proactive operation, they will register that interest by a documentary application. A flagging request document is used to register an individual, address or other unique searchable data, and the flag refers to the ability of the database to identify checks subsequently conducted on the subject.

The investigator with a flagged registered investigation is responsible for handling all the disclosure issues connected with the flagging application document and for the supporting intelligence used to justify and support registration, both initially and when the flag falls for renewal (every three months). All disclosure issues flowing from the use of a flag must be handled in accordance with the instructions in this manual.

When a check is done, therefore, it may reveal the interest of another agency. If a check is conducted against a flagged individual in any agency, that agency will inform the flag holder that another agency has an interest. (The flag holding agency does not, under normal circumstances, notify the 'enquirer' of the other organisation's interest. However, they may arbitrate or facilitate cross flow of information.)

A number of law enforcement agencies protect the dissemination of the material with a disclosure caveat. This requires that the flag holding agency be informed of any subsequent prosecution after which they will then be responsible for handling any disclosure issues relating to the disseminated material.

Whilst use of the flagging system is encouraged, it is not mandatory. For various reasons, a check cannot provide a conclusive record of subjects under investigation. A negative check against a flagged individual should not therefore preclude other reasonable lines of enquiry.

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