Commissioner of Police for the Metropolis and Others, Ex Parte Pinochet

The House of Lords considered two principal legal issues: (1) the meaning of "extradition crime" in the Extradition Act 1989 (in particular the double criminality requirement in section 2) and the correct date at which United Kingdom criminality must be tested; and (2) whether a former head of state enjoys state immunity (ratione materiae) from arrest and extradition in respect of acts of official torture. The court held that, for the double criminality rule in section 2, the relevant test is whether the conduct was an offence under United Kingdom law at the date it was committed (the conduct date), not merely at the date of request. As a result most alleged acts of torture before the Criminal Justice Act 1988 s.134 came into force were not "extradition crimes". The House also concluded, by a majority, that official torture as defined by the UN Torture Convention cannot be treated as an official function attracting continuing immunity ratione materiae; where the alleged official torture occurred after the United Kingdom implemented the Convention (and insofar as Chile had become bound), immunity did not bar extradition or prosecution. The practical consequence was to allow extradition proceedings to proceed only in relation to the limited period and charges that satisfied double criminality and fell outside immunity (notably acts of torture after the relevant Convention/implementation dates).

The respondent, Senator Augusto Pinochet (former head of state of Chile), was arrested in the United Kingdom on provisional warrants issued under the Extradition Act 1989 following extradition requests from Spain alleging widespread conspiracy, torture, hostage-taking and murder. The Divisional Court quashed the provisional warrants, holding that as former head of state Pinochet enjoyed state immunity from arrest and extradition. The Crown (on behalf of Spain) appealed to the House of Lords.

Procedural history and posture:

• Divisional Court (Queen's Bench Division) quashed both provisional warrants (28 October 1998).
• First hearing in the House of Lords, 4–12 November 1998: majority allowed the appeal (reported [1998] 3 WLR 1456), but that Committee was later found not to have been properly constituted and its judgment was set aside (15 January 1999) ([1999] 2 WLR 272).
• Rehearing before the Appellate Committee on 18–24 January and 24 March 1999, with fuller argument on issues of double criminality, the scope of the Extradition Act 1989 (notably s.2), the extra‑territorial effect of Criminal Justice Act 1988 s.134 (torture), and the scope of state immunity (State Immunity Act 1978 s.20 and Vienna Convention Article 39).

Nature of the application: extradition to Spain; the court had to decide (i) which of the allegations (as translated into English-law equivalents) were "extradition crimes" under the Extradition Act 1989; and (ii) whether Pinochet, as a former head of state, was immune from arrest and extradition for any such offences.

Issues framed:

1. Does the double criminality rule in section 2 require the conduct to have been criminal under United Kingdom law at the date of commission (the conduct date) or only at the date of the extradition request (the request date)?
2. If some charges qualify as extradition crimes, does customary international law or treaty law (notably the Torture Convention) permit a former head of state to claim immunity ratione materiae in respect of official acts of torture?

Reasoning and holdings on the issues:

• The House held (Browne-Wilkinson and others) that section 2 ought to be read so that double criminality is assessed at the conduct date. Parliament had not changed the long-established rule that the domestic criminality required to be shown is judged as at the date of commission; the statutory scheme and the history of the Extradition Act 1870/1989 indicated that result. Consequently many alleged acts of torture or conspiracy to torture before s.134 of the Criminal Justice Act 1988 came into force (29 September 1988) could not be extradited because they were not United Kingdom offences when committed.
• On state immunity the majority concluded that international law and the Torture Convention, supported by the domestic criminalisation in s.134, meant that official torture (and conspiracies to commit it) committed after the relevant implementation/ratification dates was not protected by continuing immunity ratione materiae. The Convention made clear that torture is an offence when committed by "a public official or other person acting in an official capacity" and required states either to extradite or prosecute alleged torturers found in their territory; this framework undermined the availability of a state‑function immunity in respect of official torture after the Convention/implementation dates. There were vigorous dissenting judgments, however, arguing that immunity ratione materiae should continue to be available and that any waiver by treaty must be express.

Practical result: the House allowed the appeal in part: extradition proceedings could in principle proceed only in relation to those charges that satisfied double criminality at the conduct date and were not barred by immunity (in particular acts of official torture and conspiracy to torture alleged after the relevant Convention/implementation dates). The Secretary of State's earlier authority to proceed had to be reconsidered in the light of the court's narrowing of the case.

Appeal allowed in part. The House held that (1) under the Extradition Act 1989 the double criminality requirement is to be assessed by reference to whether the conduct constituted an offence under United Kingdom law at the date of commission (the conduct date), not merely at the date of the extradition request; and (2) by a majority, official torture committed after the Torture Convention was implemented in domestic law (and after Chile's ratification) does not attract immunity ratione materiae, so a former head of state cannot rely on state immunity to bar extradition or prosecution for such official torture. Accordingly extradition proceedings may proceed only in respect of the limited charges that meet those tests; other charges (notably most alleged torture before the Criminal Justice Act 1988 s.134 came into force) are not extradition crimes or are otherwise barred.

Divisional Court (Queen's Bench Division) quashed provisional warrants (28 October 1998). First hearing in the House of Lords (4–12 November 1998): majority allowed the Crown's appeal ([1998] 3 WLR 1456), but that decision was set aside on procedural grounds (15 January 1999) ([1999] 2 WLR 272). The appeal was reheard and the Appellate Committee delivered judgment on 24 March 1999 ([1999] UKHL 17), allowing the appeal in part as to specified charges and remitting aspects for reconsideration by the Secretary of State and magistrate.