(1) This section applies if a surveillance device warrant is issued to a law enforcement officer.
(2) If the chief officer of the law enforcement agency of which the law enforcement officer concerned is a member is satisfied that the use of a surveillance device under the warrant is no longer necessary for the warrant purpose, the chief officer must--(a) take the steps necessary to ensure that use of the surveillance device authorised by the warrant is discontinued as soon as practicable, and(b) cause an application to be made for the revocation of the warrant under section 23.
(2A) The chief officer of the law enforcement agency is not required to cause an application to be made for the revocation of a warrant under section 23 if the warrant will cease to be in force within 5 days after the day on which the chief officer became satisfied the use of a surveillance device under the warrant was no longer necessary.
(3) If the chief officer is notified that the warrant has been revoked under section 23, he or she must take the steps necessary to ensure that use of the surveillance device authorised by the warrant is discontinued immediately.
(4) If the law enforcement officer to whom the warrant is issued, or who is primarily responsible for executing the warrant, believes that the use of a surveillance device under the warrant is no longer necessary for the warrant purpose, he or she must inform the chief officer of the law enforcement agency immediately.
(5) In this section--
"warrant purpose" means--(a) in relation to a warrant that is issued based on an application under section 17(1)--the purpose of enabling evidence to be obtained of the commission of the relevant offence or the identity or location of the offender, or(b) in relation to a warrant that is issued based on an application under section 17(1A)--the purpose of enabling evidence to be obtained that would be likely to support an application for a supervision or detention order under the Terrorism (High Risk Offenders) Act 2017 in respect of the inmate.