R (on the application of Purdy) (Appellant) v Director of Public Prosecutions (Respondent)
para. 9
'As a general rule English criminal law does not extend to acts committed outside the jurisdiction: Cox v Army Council [1963] AC 48 at p. 67; Treacy v DPP [1971] AC 537 at pp. 552-553. From at least the time of Henry VIII, however, murder has been recognised as an exception to this general rule'