Attorney General's Reference No 5 of 2002 (On Appeal from the Court of Appeal (Criminal Division))

Section 17 of the Regulation of Investigatory Powers Act 2000 protects the secrecy of the interception-warrant regime. It does not prevent a court from investigating whether a communication was intercepted on a public or private telecommunications system.

If the system was private, the court may also determine whether the interception was made by, or with the consent of, the person entitled to control it. Evidence from a lawful private-system interception may be admitted, subject to any other objection. This purposive construction preserves fair-trial scrutiny and gives effect to the statutory provisions governing private interception without compromising warranted surveillance.

The prosecution relied on recordings of telephone calls made on a police telecommunications network. The defendants contended that the interceptions had occurred on the public side of the network. The trial judge held that section 17 of the Regulation of Investigatory Powers Act 2000 prevented the defence from advancing that contention, although the prosecution could adduce evidence that the interception was private. The judge consequently excluded the prosecution evidence under section 78 of the Police and Criminal Evidence Act 1984, and the defendants were acquitted.

The Attorney General referred questions of law under section 36 of the Criminal Justice Act 1972. The Court of Appeal, in [2003] EWCA Crim 1632, held that section 17 did not prohibit an inquiry into whether the system was public or private, or whether a private interception was made by or with the consent of the person controlling the system. It referred those questions to the House of Lords.

1. The questions were answered unanimously in the manner proposed by Lord Bingham of Cornhill. Section 17(1) of the Regulation of Investigatory Powers Act 2000 does not prevent a criminal court from investigating whether an interception occurred on a public or private telecommunications system. That answer is the same whether the interception occurred before or after the 2000 Act came into force. Where the interception occurred on a private system, the court may investigate whether it was carried out by, or with the consent of, the person entitled to control that system.

2. Per Lord Bingham, the central purpose of section 17 is to keep warranted interception and matters pertaining to warrants outside the public domain. The prohibition applies where a warrant was obtained and where one should have been obtained. Parliament did not indicate an intention to prevent the courts from conducting the public-or-private inquiry which had been permissible under the earlier legislation.

3. Per Lord Bingham, if a court concludes that an interception occurred on a public system, the inquiry ends because section 17 protects the warrant regime. If it occurred on a private system but was unlawful, the inquiry likewise ends. If it occurred on a private system and was lawful, the intercept evidence may be admitted, subject to any other objection. That construction reflects the public interest in admitting relevant and probative evidence where secrecy concerning warranted interception is not engaged.

4. Lord Nicholls reasoned that section 18(4) and (5) expressly permit investigation of forms of lawful interception specified in sections 1(5)(c), 3 and 4. Parliament could not rationally have intended a different result for the ingredients identified in section 1(6). Such a result would impair a fair trial, make the private-interception offence ineffective in relevant circumstances and render the civil remedy in section 1(3) unworkable.

5. Lord Steyn agreed that the Act required a purposive construction. Neither its text nor the permitted external aids indicated that Parliament intended to reverse the established practice of examining whether an interception occurred on a public or private system.

6. Lord Hope held that the statutory “forbidden territory” is confined to matters whose investigation would intrude upon the surveillance and warrant regime. Questions limited to whether a system was public or private and whether the controller made or consented to the interception fall outside that territory. Lord Walker agreed, adding that section 17(2)(a)'s reference to the private-system offence preserves secrecy where a warrant is exceptionally issued for interception on a private system.

1. House of Lords: Unanimously answered the Attorney General's questions in accordance with the answers given below and affirmed that section 17 permitted the relevant inquiries: [2004] UKHL 40.

2. Court of Appeal (Criminal Division): Accepted the Attorney General's construction, answered the referred questions and referred them to the House under section 36(3) of the Criminal Justice Act 1972: [2003] EWCA Crim 1632; [2003] 1 WLR 2902.

3. Crown Court: Ruled that section 17 prevented the defence from asserting that the interception occurred on the public system. It then excluded the prosecution evidence under section 78 of the Police and Criminal Evidence Act 1984. The prosecution offered no evidence and the defendants were acquitted.