She was built at Barrow-in-Furness by Vickers Shipbuilding and Engineering. She was laid down in 1973, and launched on 3 May 1977. The ship commissioned on July 11 1980, and joined the older carriers Hermes and Bulwark in service.
The carrier's air group comprises nine Harrierss and twelve helicopters (usually all Sea Kings, either ASW or AEW variants). The carriers also provide a operational headquarters for the RN task force. The runway is 170 m long and includes the characteristic "ski jump" (initially 7° it was later increased to 12°).
For defence the carriers have a number of systems. They have either the Raytheon or the Thales Goalkeeper CIWS; they also have two 20 mm Oerlikons. Countermeasures are provided by a Thales jamming sytem and ECM system, Sea Gnat launchers provide for chaff or flare decoys. Initially the carriers were also armed with a Sea Dart SAM missile system, but these were removed in order to increase the flight deck size and to allow magazine storage for Royal Air Force Harrier GR7s.