The Nimrod has been the Royal Air Force's primary Maritime Patrol Aircraft (MPA) since the early 1970s, when it replaced the piston-engined Avro Shackleton. The RAF uses two Nimrod variants: the MR2 variant in the Maritime and Reconnaissance role; the R1 variant in a reconnaissance and electronic intelligence gathering capacity (ELINT). The Nimrod is an extensive modification of the de Havilland Comet, the world's first jet airliner.

The Nimrod MR1 entered service in 1969 and was upgraded to MR2 standard in the late 1970s. While the flight deck and general systems remained the same, the Mission System was given a significant upgrade.

The Nimrod is used in four main roles: Anti Submarine Warfare, Anti-Surface-Unit Warfare, Intelligence and Communications Support and Search and Rescue. The operating crew comprises two pilots and a flight engineer, two weapon systems officers (WSO), and a WSO who is the sensor and communications coordinator. He is, in turn, supported by a team of two ‘wet’ weapon systems operators (WSOps) and four ‘dry’ WSOps. The ‘wet’ team supervise the aircraft’s acoustic processors, which monitor active and passive sonobuoys, whilst the ‘dry’ team manage a range of radar and non-acoustic sensors. The aircraft can carry in excess of 200 sonobuoys internally, which are delivered via two unpressurised 6-buoy rotary launchers and two pressurised singleshot launchers. Offensive weapons include Sting Ray torpedoes and for self-defence the aircraft is fitted with Defensive Aids systems and may be armed with four wing-mounted Sidewinder air-to-air missiles. For SAR purposes the aircraft has a selection of air deliverable, multi-seat dinghies and survival packs.

The majority of the Nimrod’s tasking comes from the UK Maritime Air Ops Centre. Peacetime work includes worldwide surface and sub-surface surveillance and the maintenance of a permanent standby for UK and overseas operations or SAR in support of the Aeronautical Rescue Coordination Centre. SAR tasks include long-range search and shepherd, assistance to SAR helicopters and coordination of search activities as the On-Scene Commander at major incidents. The aircraft routinely operates over the sea down to 200 feet, but is limited to 300 feet at night or in bad weather.

The Nimrod MR2 has also provided a continual presence in the Middle East since late 2001. In that time, employment of the aircraft has evolved to take on an additional range of non-traditional tasks, including overland Electro-Optic IMINT (Image Intelligence) surveillance of Iraq and Afghanistan, and IMINT and communications support to coalition ground troops. The Nimrod MR2 will continue in service until it is replaced by the MRA4, which is expected to enter service around 2011.