18.This Section creates the offences of unlawful interception and a separate civil liability for unlawful interception, explains the locations and circumstances in which each is applicable, and the circumstances in which interception is lawful.
19.Subsection (1) sets out the circumstances in which interception of a communication being transmitted by a public postal service or public telecommunication system is a criminal offence. The offence is similar to that created by Section 1 of the Interception of Communications Act 1985, which this Act repeals.
“Public postal service” and “public telecommunication system” are defined in Section 2(1).
There is an exception for conduct with “lawful authority”, as to which see subsection (5).  For territorial limitation, see section 2(4).
20.Subsection (2) sets out the circumstances in which interception of a communication being transmitted by a private telecommunication system is an offence. The 1985 Act contains no equivalent of this offence. There is an exclusion for the circumstances set out in subsection (6), to which this subsection refers. However, interceptions in those circumstances give rise to a civil liability, as to which see subsection (3).
Commentary on Sections Section 1: Unlawful and authorised interception