81.Subsection (5)(b) covers conduct authorised by an interception warrant by Section 5(6). See Explanatory Notes for Section 5(6)(a) to (c).
82.Subsection (6) requires a certificate to be issued under the hand of the Secretary of State. The control exercised through the certificate has therefore to be a personal Ministerial one. There is no provision for delegation of this power to officials, even in urgent cases.
Commentary on Sections “External communications” is defined in Section 20.