Attorney General's Reference No 5 of 2002

This reference concerned the proper construction of section 17(1) of the Regulation of Investigatory Powers Act 2000 and, in particular, whether and to what extent a criminal court may investigate whether intercepted material relied on by the Crown was obtained by tapping a private as opposed to a public telecommunication system. The House held that section 17 must be read so as not to bar enquiry into whether an interception took place on a private system and, if so, whether it was lawfully authorised under the Act (notably sections 1(5)(c), 3 and 4 and the exception in section 18(4)).

Where the enquiry establishes that interception was on a public system or was private but unlawful, the material falls within the exclusion in section 17 and is excluded; where the enquiry establishes that interception was private but lawful under the specified statutory grounds the material may be admissible. The same approach applies to interceptions occurring before the 2000 Act came into force and to those after it, subject to case-specific considerations.

The Attorney General referred questions under section 36(1) of the Criminal Justice Act 1972 concerning the construction of section 17(1) of the Regulation of Investigatory Powers Act 2000. The factual background was a criminal prosecution in which the Crown relied on intercepted telephone communications obtained when police monitored extensions used by a police officer (W) on a system linking several police stations and comprising private branch exchanges connected by BT Megastream lines. The trial judge excluded prosecution evidence under section 78 PACE because, he held, section 17 prevented the defence from investigating whether the interception occurred on the public side of the system; that ruling led to acquittal and the reference.

The House examined (i) the statutory scheme created by the 2000 Act (including sections 1, 2, 3, 4, 17 and 18) and its background in earlier legislation and Strasbourg jurisprudence (notably Malone and Halford); (ii) the policy of preserving secrecy of the warrant system while permitting enquiries necessary to determine lawfulness where statutory exceptions apply; and (iii) the compatibility of a broad literal reading of section 17(1) with the Act's purpose and with the civil remedy in section 1(3).

Issues framed by the court included whether section 17(1) prevents any evidential enquiry into whether a telecommunication system is public or private; whether the answer differs for interceptions occurring before the 2000 Act; and whether, where interception was on a private system, it is permissible to adduce evidence to establish that the interception was by or on behalf of the person with the right to control the system (both before and after the Act). The House answered the first two questions in the negative and the third in the affirmative (pre-Act: yes; post-Act: yes, subject to the facts of the particular case).

The court reasoned that (a) Parliament’s purpose in Chapter 1 of the 2000 Act was to regulate interception without unduly preventing legitimate evidential enquiry; (b) section 18(4) already permits enquiry where interception is lawful by virtue of sections 1(5)(c), 3 or 4, and nothing in the Act evidenced an intention to prevent tribunals from determining whether an interception occurred on a public or private system; and (c) a purposive construction avoids frustrating the civil remedy in section 1(3) and avoids producing irrational results that would render parts of the Act unworkable.

The House answered the Attorney General's questions in the terms proposed by Lord Bingham: section 17(1) does not operate so as to bar a court from investigating whether intercepted material was obtained by tapping a private as opposed to a public telecommunication system. The court held that a tribunal may enquire whether interception was lawful under the statutory exceptions (sections 1(5)(c), 3 and 4 and the exclusion in section 1(6)) and may admit material where interception is shown to be lawful; if interception was public or private but unlawful the exclusion in section 17 operates and the material will be excluded. The same approach applies to interceptions before and after the Act (questions 1 and 2 answered No; question 3(a) Yes; question 3(b) Yes, subject to the facts). The House gave these answers to the reference and explained the rationale based on statutory purpose and precedent.

Reference under section 36(1) Criminal Justice Act 1972 following acquittal at trial; Court of Appeal considered the questions and accepted the Attorney General's arguments ([2003] EWCA Crim 1632, [2003] 1 WLR 2902) but referred the questions to the House under section 36(3); House of Lords gave its opinion in [2004] UKHL 40.