The majority of in-service Harrier 'Jump Jets' are the Harrier GR7 (two seat variant T-10). Capable of taking off and landing vertically, the Harrier is not tied to airfields with long concrete runways but can be dispersed to sites in the field close to the forward edge of the battle area.

The normal method of operation calls for a short take-off and vertical landing (STOVL), as a short ground roll on take-off enables a greater weapon load to be carried.

The second-generation GR5 and GR7 versions replaced the original Harrier GR3s in the late 1980s/early 1990s in the offensive support role. First flight of the Harrier GR7 was in 1989, and deliveries to RAF squadrons began in 1990. A total of 96 aircraft were ordered, including 62 interim GR5s which were later modified to GR7 standard.

The Harrier GR7 has received a number of upgrades with which include the fitting of new Pegasus 107 engines giving more thrust at higher temperatures as well as reduced maintenance costs having been fitted to 30 aircraft, these becoming Harrier GR7As.

In addition, a major upgrade to the aircraft's avionics and weapons systems is under way that will enable the Harrier to carry a variety of current and future weapons. These include Maverick air-surface missiles, Brimstone anti-armour missiles and AIM-9L Sidewinder air-to-air missiles for self-defence.

A new, stronger composite rear fuselage will also be fitted. These aircraft will become Harrier GR9s, whilst those with the uprated engines and weapons systems will be Harrier GR9As. The programme also includes an upgrade of the two-seater T10 aircraft to the equivalent GR9 standard known as the Harrier T12.

No 800 and No 801 Naval Air Squadrons operates 9 x Harrier GR7/7A each from RAF Cottesmore.