Bartle and the Commissioner of Police for the Metropolis and Others, Ex Parte Pinochet, R v.

The House was required to decide whether the respondent, a former Head of State, enjoyed immunity from arrest and extradition in the United Kingdom in respect of alleged official acts said to amount to torture and hostage-taking and related offences. Key statutory and international instruments considered included the State Immunity Act 1978 (in particular section 20), the Diplomatic Privileges Act 1964 (and Articles 29, 31 and 39 of the Vienna Convention on Diplomatic Relations), the Extradition Act 1989 (section 8) and the extra‑territorial offences created by the Criminal Justice Act 1988 (section 134) and the Taking of Hostages Act 1982.

The majority held that the statutory scheme and principles of international law must be construed so that immunity ratione materiae for official acts does not cover acts which, by international law and by the terms of the statutes giving extra‑territorial criminal jurisdiction, fall outside functions of a Head of State. The majority therefore concluded that the respondent was not entitled to continue to rely on former Head of State immunity in respect of certain alleged crimes and allowed the appeal. Dissenting speeches emphasised the traditional scope of immunity ratione materiae, the need for restraint and the view that the existing international law position did not clearly deprive former Heads of State of immunity for official acts.

The respondent, alleged to have been responsible for killings, disappearances and torture while Head of State of Chile, was arrested in London on provisional warrants issued under section 8(1)(b) of the Extradition Act 1989 at the request of Spanish authorities. The respondent applied for habeas corpus and for judicial review to quash the provisional warrants and claimed immunity from arrest and extradition on the basis that he was Head of State during the period in question and accordingly entitled to immunity in respect of official acts.

The Divisional Court quashed the provisional warrants and certified a point of law of general public importance on the scope of immunity enjoyed by a former Head of State from arrest and extradition proceedings in the United Kingdom. The case was taken to the House of Lords where the issues were framed as:

• (i) whether a former Head of State has immunity at common law or under the State Immunity Act 1978/section 20;
• (ii) whether international conventions on torture, hostage-taking and genocide or domestic statutes implementing them remove or limit such immunity;
• (iii) whether the act of state/non‑justiciability doctrines require the courts to decline jurisdiction.

The House examined the scope of Part I and Part III of the State Immunity Act 1978, the Diplomatic Privileges Act 1964 as giving force to the Vienna Convention, and the relevant international conventions (Convention against Torture; Taking of Hostages Convention; Genocide Convention). It analysed the meaning of "acts performed in the exercise of his functions" and whether grave crimes such as torture or hostage-taking can be characterised as official acts for the purpose of immunity. The majority concluded that where international law and enacted criminal law give States jurisdiction over such crimes and where the nature of the act is not properly an exercise of Head of State functions, immunity does not bar extradition or prosecution; the minority took a more cautious approach, stressing the continuing force of immunity ratione materiae and non‑justiciability. The Court therefore determined whether statutory immunity applied and whether the act of state doctrine barred the proceedings, giving detailed reasons on both statutory construction and international law context.

appeal allowed; the majority concluded that the statutory and international law framework does not necessarily preserve an absolute immunity for a former Head of State in respect of alleged acts which cannot properly be characterised as acts performed in the exercise of his functions as Head of State (notably certain acts of torture and hostage‑taking), and that act of state/non‑justiciability did not bar the proceedings on the facts and legal analysis before the House.

On appeal from the Divisional Court of the Queen's Bench Division which had quashed provisional warrants for arrest and certified a point of law concerning the scope of former Head of State immunity; leave to appeal to the House of Lords was granted. (Proceedings originated from provisional warrants issued under section 8(1)(b) of the Extradition Act 1989.)