The Avro Shackleton is a British long-range maritime patrol aircraft (MPA) used by the Royal Air Force (RAF) and the South African Air Force (SAAF). It was developed by Avro from the Avro Lincoln bomber, which itself had been a development of the famous wartime Avro Lancaster bomber.The Shackleton was developed during 1946 as part of Britain's military response to the rapid expansion of the Soviet Navy, in particular its submarine force. Produced as the primary type equipping RAF Coastal Command, the Type 696, as it was initially designated, incorporated major elements of the Lincoln, as well as the Avro Tudor passenger aircraft, and was furnished with extensive electronics suites in order to perform the anti-submarine warfare (ASW) mission along with a much improved crew environment to accommodate the long mission times involved in patrol work. Being known for a short time as the Lincoln ASR.3, it was decided that the Type 696 would be named Shackleton in service, after the polar explorer Sir Ernest Shackleton.The Shackleton entered operational service with the RAF in April 1951. It was used primarily in the ASW and MPA roles, but it was also frequently deployed as an aerial search and rescue (SAR) platform and for performing several other secondary roles such as mail delivery and as a crude troop-transport aircraft. In addition to its service with the RAF, South Africa also chose the Shackleton to equip the SAAF. In South African service, the type was operated in the maritime patrol capacity between 1957 and 1984.During the 1970s, the Shackleton was replaced in the maritime patrol role by the jet-powered Hawker Siddeley Nimrod. During its later life, a small number of the RAF's existing Shackleton’s received extensive modifications in order to adapt them to perform the airborne early warning (AEW) role. The type continued to be used in this support capacity until 1991, when it was replaced by the Boeing E-3 Sentry AEW aircraft. These were the last examples of the type remaining in active service.