When considering whether (or when) to release information to the public, police have conflicting motivations, which are summarized by the Association of Chief Police Officers (of England, Wales, and Northern Ireland) [A]:
- Suspects have rights regarding the release of their information.
- The community has some right to know about crime in their area.
- The agency has the right to withhold information based on its operational concerns, but otherwise should make information available.
Police are allowed to keep information a secret, and are encouraged to in some cases. Information should generally be kept secret until charges are filed. Agencies may open themselves up to libel charges if they release names of people who ultimately are not charged with a crime.
ACPO’s guidance is not to release information on suspects except when necessary to:
- Prevent or detect a crime
- Assisting the investigation by apprehending a suspect or finding witnesses
- Reassure or inform the public
The public has the right to know about crimes committed in their area. Beyond the police's need to reassure or inform the public about crimes, the guidance is to allow circumstances (like a strong local or national interest) to be a factor when deciding whether to release information or not.
[A] The linked guidance applies to the release of images of suspects. Other articles refer to ACPO guidance on the release of names, but I haven't been able to find that document online. The principles named in their guidance seem transferable between the two cases.
[B] This is all similar to how agencies (both law enforcement and non-law enforcement) in the United States handle releasing information. Information is presumed to be public, but may be closed at their discretion. This is typically done for confidential information (like personal identification) and operational concerns.