The present Ministry of Defence (MOD)was formed by the amalgamation in 1964 of the Ministry of Defence, the Admiralty, the War Office and the Air Ministry, and the inclusion in 1971 of the Ministry of Aviation Supply. In 1973, the operations of the Atomic Weapons Establishment were transferred from the UK Atomic Energy Authority to the MOD.
The principal activity of the Department is to deliver security for the people of the United Kingdom and the Overseas Territories by defending them, including against terrorism, and to act as a force for good by strengthening international peace and stability.