(1)  A surveillance device warrant may be revoked at any time before the expiration of the period of validity specified in it by –

(a) the Supreme Court, if the Supreme Court issued the warrant or the extension or variation of the warrant; or

(b) a magistrate, if a magistrate issued the warrant.

(2)  The Supreme Court or a magistrate may revoke a surveillance device warrant after receiving a report under section 29 in respect of the warrant.

(3)  The Supreme Court or magistrate who revokes a warrant must give notice of the revocation to the chief officer of the law enforcement agency of which the law enforcement officer to whom the warrant was issued is a member.

(4)  If the chief officer is notified that the warrant has been revoked, he or she must take the steps necessary to ensure that use of the surveillance device authorised by the warrant is discontinued immediately.