From Pima Air Museum:
Developed in Great Britain by Hawker Siddeley (later part of British Aerospace) the Harrier is one of only two vertical/short takeoff and landing jets to go into full production. First placed in service by the Royal Air Force and Royal Navy the Harrier first saw combat in the 1982 Falklands War between Britain and Argentina.
The Harrier II is a radically upgraded version of the original Harrier developed as a joint venture between British Aerospace and McDonnell-Douglas. The aircraft featured numerous changes to enhance its capabilities. These include a lighter weight construction using composite materials, a larger wing, and increased payload. Externally it is nearly identical to the AV-8B used by the United States Marine Corps. There are, however, many internal differences. The first British version of the Harrier II, the GR.5, entered RAF service in 1987 with the first squadron declared operational in 1989. Most of the forty-one GR.5s built were eventually upgraded to GR.7 status with improved night and all-weather combat capabilities. The Harrier II was retired from British service in 2010.
https://pimaair.org/museum-aircraft/british-aerospace-harrier-gr-5/