R v Bow Street Metropolitan Stipendiary Magistrate ex parte Pinochet Ugarte (No 3)

Facts

• General Augusto Pinochet was the former President and military dictator of Chile (1973 to 1990)
• In 1998, while in London for medical treatment, Spain issued an international arrest warrant alleging torture, hostage-taking, and murder during his regime
• Pinochet was arrested and extradition proceedings commenced
• Pinochet claimed immunity as a former head of state under the State Immunity Act 1978
• The case reached the House of Lords after the first hearing was set aside due to Lord Hoffmann's undisclosed Amnesty International connection

Issue

1. Whether a former head of state could claim immunity from criminal prosecution for acts of systematic torture committed during his time in office.

Held

• The House of Lords held (by majority, 6-1 on the immunity point) that Pinochet could not claim immunity
• Former heads of state enjoy immunity ratione materiae only for acts performed in their official capacity
• Systematic torture cannot be characterised as an official function of a head of state
• Once the United Nations Convention against Torture (UNCAT) came into force for the UK, Chile, and Spain, the immunity defence fell away
• The prohibition of torture is a jus cogens norm that overrides claims of sovereign immunity

Ratio Decidendi

A former head of state retains immunity ratione materiae for official acts performed during office. However, the commission of acts prohibited as international crimes under jus cogens norms (such as systematic torture) cannot qualify as official acts of a head of state. No state can claim that the systematic use of torture falls within the legitimate function of a head of state. The entry into force of UNCAT for the relevant states created universal jurisdiction over torture and impliedly removed immunity for such acts.