Another example of retrospective law-making came in the form of the War Crimes Act 1991, which empowers the UK courts to punish war crimes committed by persons who were not subject to British jurisdiction at the time when the crimes were committed. Note, however, that while retrospective criminal legislation is prohibited by the ECHR, art 7, there is an exception: 'the trial and punishment of any person for any act or omission which, at the time when it was committed, was criminal according to the general principles of law recognised by civilised nations'. The War Crimes Act 1991 comes within the scope of this exception.