6. Existence and non-existence of a state of war.

At common law no state of war exists between the United Kingdom and a foreign state until there has been a formal declaration of war by the Crown or hostilities have been commenced by the authority of the Crown on the basis that those hostilities constitute a 'war'1. Similarly a war may be terminated only by the authority of the Crown, and this is usually effected by a treaty of peace and announced to the nation by proclamation or Order in Council2. A certificate of the Secretary of State for Foreign and Commonwealth Affairs to the effect that the