(1) A surveillance device warrant may, by instrument in writing, be revoked by an eligible Judge or nominated ART member on his or her own initiative at any time before the expiration of the period of validity specified in the warrant.
(2) If the circumstances set out in subsection 21(2), (3) or (3A) apply in relation to a surveillance device warrant, the chief officer of the law enforcement agency to which the law enforcement officer to whom the warrant was issued belongs or is seconded must, by instrument in writing, revoke the warrant.
(3) The instrument revoking a warrant must be signed by the eligible Judge, the nominated ART member or the chief officer of the law enforcement agency, as the case requires.
(4) If an eligible Judge or nominated ART member revokes a warrant, he or she must give a copy of the instrument of revocation to the chief officer of the law enforcement agency to which the law enforcement officer to whom the warrant was issued belongs or is seconded.
(5) If:
(a) an eligible Judge or nominated ART member revokes a warrant; and
(b) at the time of the revocation, a law enforcement officer is executing the warrant;
the law enforcement officer is not subject to any civil or criminal liability for any act done in the proper execution of that warrant before the officer is made aware of the revocation.