Investigatory Powers Act 2016 (c. 25)
Part 2 — Lawful interception of communications
Chapter 1 — Interception and examination with a warrant
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(5)
A targeted interception warrant or mutual assistance warrant also authorises
the following conduct (in addition to the conduct described in the warrant)—
(a) any conduct which it is necessary to undertake in order to do what is
expressly authorised or required by the warrant, including—
(i) the interception of communications not described in the
warrant, and
(ii) conduct for obtaining secondary data from such
communications;
(b) any conduct by any person which is conduct in pursuance of a
requirement imposed by or on behalf of the person to whom the
warrant is addressed to be provided with assistance in giving effect to
the warrant;
(c) any conduct for obtaining related systems data from any postal
operator or telecommunications operator.
(6)
For the purposes of subsection (5)(c)—
“related systems data”, in relation to a warrant, means systems data
relating to a relevant communication or to the sender or recipient, or
intended recipient, of a relevant communication (whether or not a
person), and
“relevant communication”, in relation to a warrant, means—
(a) any communication intercepted in accordance with the warrant
in the course of its transmission by means of a postal service or
telecommunication system, or
(b) any communication from which secondary data is obtained
under the warrant.
(7)
For provision enabling the combination of targeted interception warrants with
certain other warrants or authorisations (including targeted examination
warrants), see Schedule 8.
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Obtaining secondary data
(1)
This section has effect for the purposes of this Part.
(2)
In relation to a communication transmitted by means of a postal service,
references to obtaining secondary data from the communication are references
to obtaining such data in the course of the transmission of the communication
(as to which, see section 4(7)).
(3)
In relation to a communication transmitted by means of a telecommunication
system, references to obtaining secondary data from the communication are
references to obtaining such data—
(a) while the communication is being transmitted, or
(b) at any time when the communication is stored in or by the system
(whether before or after its transmission).
(4)
“Secondary data”—
(a) in relation to a communication transmitted by means of a postal
service, means any data falling within subsection (5);
(b) in relation to a communication transmitted by means of a
telecommunication system, means any data falling within subsection
(5) or (6).