Where the chief officer of police for any police area receives a complaint from a member of the- public against a member of the police force for that area he shall (unless the complaint alleges an offence with which the member of the police force has then been charged) forthwith record the complaint and cause it to be investigated and for that purpose may, and shall if directed by the Secretary of State, request the chief officer of police for any other police area to provide an officer of the police force for that area to carry out the investigation.

A chief officer of police shall comply with any request made to him under subsection (1) of this section.

On receiving the report of an investigation under this section the chief officer of police, unless satisfied from the report that no criminal offence has been committed, shall send the report to the Director of Public Prosecutions.