This chapter tackles intrusive surveillance, which involves actions that constitute crimes or torts. It talks about the deployment of a listening device at private residential premises or the attachment of a location-tracking device to a vehicle, which could involve trespass and criminal damage. It also analyzes the authorization criteria for property interference and for intrusive surveillance that must be considered separately by the authorizing officer. The chapter emphasizes how arguments justifying the necessity and the proportionality of an intrusive surveillance tactic may not find justification for the necessity or the proportionality of interfering with property to conduct intrusive surveillance. It cites Section 27(2) RIPA2000 that states that a person shall not be subject to civil liability in respect of any conduct that is incidental to the authorized conduct.