s 27 Lawful surveillance etc.
(1) Conduct to which this Part applies shall be lawful for all purposes if— (a) an authorisation under this Part confers an entitlement to engage in that conduct on the person whose conduct it is; and (b) his conduct is in accordance with the authorisation. (2) A person shall not be subject to any civil liability in respect of any conduct of his which— (a) is incidental to any conduct that is lawful by virtue of subsection (1); and (b) is not itself conduct an authorisation or warrant for which is capable of being granted under a relevant enactment and might reasonably have been expected to have been sought in the case in question. (3) The conduct that may be authorised under this Part includes conduct outside the United Kingdom. (4) In this section “ relevant enactment ” means— (a) an enactment contained in this Act or the Investigatory Powers Act 2016 ; (b) section 5 of the Intelligence Services Act 1994 (warrants for the intelligence services); or (c) an enactment contained in Part III of the Police Act 1997 (powers of the police and of officers of Revenue and Customs).