In May 1965, the Defence Ministries of France and the UK agreed on a joint programme to develop a supersonic trainer and tactical strike aircraft. France had already decided upon the Brequet 1221 design and this, together with the Rolls-Royce/Turbomeca Adour engine became the basis of the Jaguar.  Design leadership was with both Brequet Aviation and the British Aircraft Corporation, so the companies established the joint company SEPECAT to coordinate production. 

The first two-seat Jaguar trainer flew in September 1968 and the first single-seater in March 1969. Production GR.1 aircraft entered RAF service with 54 sqn in March 1974. The French Air Force phased the type into service earlier in June 1973. The GR.1 for the RAF was a single-seat all-weather strike and ground attack fighter equipped with NAVWASS (navigating and weapons aiming sub-system) enabling it to attack without using radars. 

Based mostly in Germany, RAF Jaguars were used for rapid deployment and regional reinforcement, and others flew in the tactical nuclear strike role carrying the WE177 bomb. Upgraded GR.1A Jaguars flew successfully in the 1990 Gulf War, where 12 aircraft flew 612 combat sorties without loss. The final Jaguars were retired from RAF service in April 2007.