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Relations with other prosecuting agencies and the Prosecutors’ Convention

Updated: 24 February 2023; 17 May 2023; 25 October 2023|Legal Guidance


Statutory Duty

The CPS has a statutory duty under section 3(2)(a) of the Prosecution of Offences Act 1985 (the Act) to take over the conduct of all criminal proceedings, other than specified proceedings, instituted by or on behalf of the police. This duty is subject to the Criminal Justice Act 1987 (establishment and duties of the Serious Fraud Office).

The CPS also has discretion to take over criminal proceedings in any other case under Section 6(2) of the Act.

Other government departments also have a statutory duty to prosecute alongside the CPS. Prosecutions are regularly brought by other prosecuting agencies where the body concerned has a particular expertise or statutory interest. In general the CPS will neither wish nor need to intervene in such cases.

However, there are some circumstances in which it may be appropriate to:

  • assign CPS proceedings to be conducted by another prosecuting agency where it is agreed that they have the lead or major interest.
  • take over the conduct of proceedings which would otherwise be pursued by another body; the CPS will only do this against the wishes of the other prosecuting agency or body in wholly exceptional circumstances where all other avenues of discussion have been exhausted.

Prosecutors’ Convention

This is an agreement between the CPS and a series of prosecution agencies to abide by broad principles where two or more signatories have a common interest in an investigation or prosecution.

The Convention, which can be found at Annex A of this guidance was published on 11 December 2012. Where a signatory to the Convention is involved or has an interest in a related prosecution the principles of the Convention are mandatory.

Where a prosecuting agency is involved which is not a signatory then the principles of the Convention provide a framework for best practice and should, where practicable, be followed.

Signatories to the Convention should encourage associated prosecuting agencies and investigators to abide by the spirit of the Convention.


Institution of Proceedings

Difficulties may arise when it is not clear who has instituted proceedings or there are overlapping interests and the same subject is being prosecuted by different agencies, or a single investigation has revealed offences which are normally prosecuted by separate agencies.

For the purpose of section 3(2)(a) of the Act, proceedings are instituted by the police only when they have investigated, arrested and brought the arrested person to the custody officer. A case is not instituted by the police simply because a custody officer at a police station charges the suspect: R v Stafford Justices ex parte Customs and Excise Commissioners (1991) 2 All ER 201.

The duty in section 3(2)(a) of the Act likely does not arise if any of the following factors apply:

  • the police did not conduct the majority of the investigation; 
  • the police were only involved in overseeing a search, effecting an arrest or assisting other investigators in the conduct of an interview; 
  • another agency is in possession of all the main exhibits; 
  • someone other than a police officer is named on the charge sheet as the person accepting the charge or as the officer in the case.

Common Prosecuting Interest

Proceedings in the magistrates' court or the Crown Court can only be properly joined together when the charges:

  • are founded on the same facts or evidence, or 
  • form, or are part of, a series of offences of the same or similar character

If the cases can be properly joined a prosecutor should also have regard to the following:

  • the evidential advantages of a single set of proceedings
  • fairness to the defendant
  • the interests of witnesses
  • any financial savings which may result from a single set of proceedings

In deciding who should have conduct of a single set of proceedings, a prosecutor should discuss the issue with the other prosecuting agency concerned and consider the “factors for early consideration” in the Prosecutors’ Convention, at Annex A. When it remains necessary for separate sets of proceedings conducted by the CPS and another prosecuting agency it is highly desirable that the same prosecution advocate should be instructed. Where the CPS is dealing with overlapping investigations, regard may be had to: Disclosure Manual Legal Guidance - Chapter 32 - Co-ordination of Disclosure Issues involving Multiple Police Force and Multiple Agency Investigations Within the UK.

Assigning Proceedings

Where it is agreed that another prosecuting agency should take over the conduct of criminal proceedings in their entirety, it is possible to assign the proceedings instituted on behalf of the police under the terms of section 5(1) of the Act.

Assignment gives the other agency day to day conduct of the proceedings, but the case remains the responsibility of the CPS. The duty of review does not cease and the CPS should continue to deal with:

  • the representations to be made as regards bail or custody
  • the acceptance of pleas
  • disclosure.

Any person conducting proceedings assigned under section 5(1) shall have all the powers of a Crown Prosecutor but shall exercise those powers subject to any instructions given by a Crown Prosecutor.

Requests to Take Over Proceedings

Where the CPS is asked by an outside agency to institute or take over proceedings in the absence of a related police prosecution, it is only in wholly exceptional cases that the CPS exercise its authority to take over proceedings under section 6(2) of the Act against the wishes of the prosecuting agency.

The decision to take over proceedings should always be taken at Chief Crown Prosecutor level and the CPS should only accede to such a request if it is satisfied that wholly exceptional reasons are substantiated. For instance, that the proceedings have been brought, or not brought, or withdrawn, in blatant disregard of the Code for Crown Prosecutors.

Where the CPS takes over the conduct of proceedings it assumes complete control of them.

Active Intervention

In certain circumstances, the CPS will take the initiative and intervene in a private prosecution conducted by a body which regularly institutes criminal proceedings and which is recognised as possessing a particular expertise about matters in respect of which it prosecutes. It will be very unusual for the CPS to intervene in such a case, but the wider public interest may on rare occasions support intervention particularly where:

  • there is a danger that the prosecutor is about to stop an undoubtedly important case for what may be an inappropriate reason
  • where the police, the CPS, or any other public prosecutor had promised the defendant that they would not be prosecuted at all, or the matter would be dealt with by an out of court disposal, not including cases where the prosecuting agency had merely informed the defendant that they would not be bringing or continuing proceeding – cases which, applying the Code for Crown Prosecutors and the CPS guidance on abuse of process, would highly likely be found to be an abuse of process.

Provision of Advice

The CPS should only provide early advice or a charging decision where it is clear from the investigation that the CPS is the appropriate body to do so. Even where the police have investigated, the prosecutor may want to satisfy themselves that another agency has been informed and should seek to discuss the matter with that agency if they might have an interest in the prosecution.

Assigned Cases

Where another prosecuting agency has the major interest in a prosecution or primacy has been agreed it may be appropriate to consider assigning CPS proceedings to that agency. Where a case is assigned under Section 5 of the Prosecution of Offences Act 1985, a prosecutor must send standard letters of assignment to (where appropriate):

  • the other prosecuting agency 
  • the defendant’s solicitors
  • the police
  • the court.

In assigned cases the CPS should not withdraw or discontinue the case.

Assigned Cases: Costs

When criminal proceedings are assigned under section 5 of the Act:

  • the CPS must not ask the other prosecuting agency to seek any costs which incurred by the CPS
  • it is not appropriate to make any contribution towards the expenses of the other prosecuting agency in conducting the CPS part of the case.

When the CPS take over the conduct of a case under section 6(2) of the Act, the CPS must only seek the costs the CPS has incurred in the conduct of the case. This does not apply where the CPS takes over the conduct of private prosecutions. Where the conduct of a private prosecution is taken over by the CPS the power of the court to order payment of prosecution costs out of Central Funds extends only to the period prior to the intervention of the CPS: see Criminal Practice Directions 2015 Division X Costs, paragraph 2.6.5.

Specific Examples

Work Related Deaths - Health and Safety Executive (HSE)

The CPS is a signatory to the Work Related Deaths Protocol.

The protocol builds on the Prosecutors’ Convention and extends the principles of coordinated decision making to encompass the investigation stage.

The principles of the protocol must always be followed. Where there is an issue that impacts upon a principle articulated in the protocol the matter should be drawn to the attention of the relevant Chief Crown Prosecutor. They may wish to consult the National Liaison Committee responsible for the strategic overview of relations between the signatories of the Protocol and other interested parties who also attend, such as representatives from the Coroners' Society and the Independent Office for Police Conduct.

Manslaughter/Corporate Manslaughter - HSE

Where consideration is given to charging an individual with manslaughter in a situation envisaged under the Protocol, police should seek the advice of the CPS. The referral criteria provides for when such cases must be referred to Special Crime and Counter Terrorism Division.

Prosecution Under the Health and Safety at Work etc Act 1974 (HSWA 1974) - HSE

Section 38 HSWA 1974 provides that proceedings for an offence under any of the provisions of the Act shall not be instituted except by an HSE inspector, the Environment Agency or the Natural Resources Body for Wales or by or with the consent of the Director of Public Prosecutions.

Where the CPS is approached for the consent of the DPP, this can be given by any Crown Prosecutor.

The Health and Safety Executive may refer an incident to the police with a view to investigation for offences other than under the HSWA 1974 and the CPS may give early advice or make a charging decision in relation to those offences.

Where additional HSWA 1974 charges are proposed, the Crown Prosecutor may find it helpful to discuss the matter with HSE lawyers.

In all cases where HSE inspectors were involved in an investigation either in the lead or assisting police, the HSE will wish to recover their costs. An application, informed by discussion with the HSE and made in accordance with the law and the Practice Direction on Costs, should be made to the sentencing court.

Service Prosecuting Authority (SPA)

The Service Prosecuting Authority (SPA) was formed on the 1st January 2009 (with the incorporation of the Navy Prosecution Authority, Army Prosecuting Authority and Royal Air Force Prosecuting Authority).

The role of the SPA is to review cases referred to it by the Service Police or Chain of Command and to prosecute appropriate cases at Court Martial or Service Civilian Court.

A protocol regarding the exercise of criminal jurisdiction in England and Wales was agreed in 2023 between the Director of Public Prosecutions and the Director of Service Prosecutions, superseding the 2016 protocol.

Employment Tribunals

Employment tribunals operate subject to the provisions of the Employment Tribunals Act 1996.

They have the power to secure the attendance of witnesses and the production of documents by the issue of summonses.

Section 7(4) of the Employment Tribunals Act 1996 provides that a person who without reasonable excuse fails to attend the tribunal to give evidence, produce documents, furnish information when required to do so, is guilty of an offence and liable on summary conviction to a fine not exceeding level 3 on the standard scale.

Generally speaking, the police will not be involved in these cases and the duty to prosecute does not arise. The power to prosecute offences referred by an Employment Tribunal comes from section 6(2) of the Act, who will provide the evidence. CPS may, however, invite the police to conduct an investigation.

Serious Crime Prevention Orders (SCPOs)

See the guidance on SCPOs for the Memorandum of Understanding, to which the CPS is a signatory, whereby the CPS may apply for SCPOs on behalf of other prosecuting agencies.

Annex A - Prosecutors’ Convention


The Prosecutors’ Convention provides a mechanism for prosecutors, investigating bodies and regulators to coordinate at an early stage and determine a strategic plan.

Purpose of the Prosecutors’ Convention

The Convention sets out the responsibilities of prosecutors where a suspect’s conduct could be dealt with by criminal or civil/regulatory sanctions and/or where more than one prosecuting authority and investigating body share the power to take action.

In such cases, depending on the extent to which more than one authority is pursuing or wishes to pursue an investigation, decisions will have to be taken about whether and how investigations should proceed and as to the choice of criminal charges or civil or regulatory sanction.

The aim is to ensure that cases are conducted in a way that is just and which best serves the overall public interest, so that the public can have confidence in the outcome. Through the Convention, Prosecuting Authorities commit themselves to:

  • Actively managing the interface with other prosecutors and investigators from the earliest possible stage;
  • Working together in a co-ordinated manner to ensure that decisions in individual cases are taken promptly and that they serve the overall public interest, having regard to the nature and seriousness of the harm and offences alleged; and
  • Enforcing the law in a fair and effective way.

The Prosecutors’ Responsibilities

These are:

To appreciate the broader picture affecting the different prosecuting agencies, investigating bodies and regulators.

To consider the nature of the conduct being investigated and to identify as early as possible any interests shared with another investigative authority, prosecutor or regulatory body. Prosecutors are likely to be advising from an early stage in an investigation and are in a good position to identify any links that have not already been made.

To establish the nature or scope of any overlapping interest in the case and any relevant criteria for decisions. The aim is to make an informed decision about the most appropriate means of proceeding in the public interest.

To establish effective lines of communication from an early stage as the best way to secure co-ordination.

To work together to develop an agreed case management strategy and to co-ordinate decisions:

  • To check whether there is an existing operational MOU or case plan between the relevant agencies. Consider drawing up such an MOU for the individual case once the case strategy is agreed
  • Where investigations are proceeding at different rates, prosecutors should advise on the modification of investigation plans to improve the prospects of co-ordinated decisions and efficiency; and to ensure that significant decisions are taken with due regard to the potential impact on any other investigation or prosecution
  • Where prosecution is or may be needed in the public interest, to ensure that the right charges are brought and that the right prosecuting authority or prosecuting authorities proceed in a way that best reflects the nature and seriousness of the offences
  • Where action falling short of prosecution by one or more authorities may be considered more appropriate, applying established policies and principles, prosecutors will encourage agreement about which civil or regulatory orders or sanctions are warranted and who is best placed to pursue them
  • Prosecutors will ensure that jointly conducted or related criminal proceedings are pursued fairly, complying with disclosure (including third party disclosure) obligations and ensuring that specialist advice is obtained where this could improve the conduct or presentation of the case; and
  • Prosecutors will work with colleagues to co-ordinate the announcement of decisions to individuals and to the public.

Factors for Early Consideration

Subject to the application of more detailed case management protocols (such as those referred to below) preliminary discussions should focus on the following as a minimum:

  • The nature and focus of any parallel interest in the conduct under investigation; the powers and sanctions that may be applicable and any decision making criteria;
  • The stage that any investigation or investigations have reached;
  • Whether any investigation or prosecution could or should be jointly conducted. If a joint investigation is not possible, the question will be how best to co-ordinate related investigations and prosecutions;
  • Which agency is best placed to take lead responsibility for any prosecution? This may depend on a variety of factors including the nature of the most serious offences and where the most relevant expertise lies;
  • The timing of any proceedings;
  • Mechanisms for preserving and sharing evidence and information; and any relevant gateways or legal provisions;
  • The need for specialist or expert prosecutors’ advice;
  • Arrangements for the service of evidence and the retention and disclosure of unused material to ensure that disclosure obligations are fulfilled, subject to any legal constraints; and
  • Any other aspect of case management that is relevant in the particular case.

In circumstances where prosecution by more than one authority cannot be avoided or where an investigation results in a joint or related prosecution, the agencies involved should co-ordinate the communication of their decisions to individual suspects and any victims; as well as co-ordinating any public announcements about prosecution decisions, preferably by way of a joint press statement.

Effective Operation of the Convention

The Head of each Prosecuting Authority or Team will be, or will name, the Prosecutors’ Convention Senior Responsible Officer for that authority (SRO). The Prosecutors’ Convention SRO will be responsible for:

  • Providing the initial point of contact for inter-agency co-ordination purposes;
  • Ensuring that there is an identified and accountable line of effective communication between each agency, to include regular structured contacts and oversight of the case management strategy;
  • Monitoring the way in which the Convention is given effect;
  • Taking prompt action to resolve any difficulties or disagreements that arise as to how the case should be best be approached. The expectation is that problems will be resolved by the prosecuting authorities, where necessary at the level of the Head of the relevant authorities. The Attorney General’s Office is available to assist by giving guidance where this would be helpful.

The Prosecutors’ Convention SRO will ensure that prosecutors are aware of the Convention; that they have easy access to it; and will give any advice and guidance they may need from the SRO in individual cases.

The SROs will be responsible for ensuring that their authorities and prosecutors as a whole learn from experience in conducting individual cases and use it to inform and improve future case handling, whether a case illustrates the benefits of good practice or whether problems have been faced and overcome.

Where they consider it advantageous or desirable, prosecuting authorities (including investigators and others) may develop separate protocols to deal with specific areas of overlap in working practice, outlining in more detail how the aims, objectives and principles of the Convention are to be fulfilled in that context.

Existing supplementary protocols include:

  • Work-Related Deaths Protocol (the signatories to the protocol are: Crown Prosecution Service, British Transport Police, Health and Safety Executive, Local Government Association, National Police Chiefs’ Council, Care Quality Commission, Care and Social Services Inspectorate Wales, Chief Fire Officers’ Association, Healthcare Inspectorate Wales, Maritime and Coastguard Agency, Medicines and Healthcare products Regulatory Authority: Medical Devices Division, Office for Nuclear Regulation, Office of Rail and Road and Welsh Local Government Association).
  • Guidelines on the Investigation of Cases of Interest or Concern to the Financial Services Authority or other Prosecuting Authorities and Investigating Agencies (these guidelines concern the following bodies: Financial Conduct Authority, Serious Fraud Office, Department for Energy and Industrial Strategy, CPS, National Police Chiefs' Council, Crown Office and Procurator Fiscal Service, Public Prosecution Service for Northern Ireland, Association of Chief Police Officers in Scotland).
  • Third party disclosure protocol (CPS, Serious Fraud Office, National Police Chiefs' Council and His Majesty's Revenue and Customs).
  • Arrangements between civilian and military prosecuting and investigating authorities governing how they will work together, decide issues of jurisdiction and where necessary decide how an allegation will be investigated. Some of these protocols are currently being revised in the light of legislative change.

Signatories will encourage associated prosecuting authorities and investigators to abide by the spirit of this Convention.


The parties to this Convention are those prosecuting authorities who have adopted it by signing the attached schedule.

Schedule to the Prosecutors' Convention

  1. Attorney General's Office
  2. Civil Aviation Authority
  3. Crown Prosecution Service
  4. Department for Business, Energy and Industrial Strategy
  5. Department for the Environment, Food and Rural Affairs
  6. Department for Work and Pensions
  7. Environment Agency
  8. Financial Services Authority
  9. Food Standards Agency
  10. Gambling Commission
  11. Health and Safety Executive
  12. Information Commissioner’s Office
  13. Maritime and Coastguard Agency
  14. Office of Fair Trading
  15. Office of Rail Regulation
  16. Revenue and Customs Prosecutions Office (now incorporated with Crown Prosecution Service)
  17. Serious Fraud Office, and
  18. Service Prosecuting Authority.
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