R (Pinochet Ugarte) v Bow St Metropolitan Stipendiary Magistrate [2000] 1 AC 61,[1] 119 and 147 is a set of three UK constitutional law judgments by the House of Lords that examined whether former Chilean dictator Augusto Pinochet was entitled to claim state immunity from torture allegations made by a Spanish court and therefore avoid extradition to Spain.

[2] In the first judgment, a panel of five judges ruled that Pinochet, as a former head of state, was not entitled to immunity from prosecution for the crimes of torture and could therefore be extradited to Spain to face charges.

[1] However, in a subsequent judgment that was to prove controversial, the ruling was set aside (R v Bow Street Metropolitan Stipendiary Magistrate, ex parte Pinochet Ugarte (No 2) (Pinochet II) following revelations that one of the Law Lords had links to one of the intervenors in the case, Amnesty International, thereby creating an appearance of bias.

[4] Pinochet had been accused by Spanish judge Baltazar Garzon of torture, a crime under international law that can be prosecuted in any country under the doctrine of universal jurisdiction.

Given this state of international law, it seems to me difficult to maintain that the commission of such high crimes may amount to acts performed in the exercise of the functions of a Head of State.... International law has made plain that certain types of conduct, including torture and hostage-taking, are not acceptable conduct on the part of anyone.