The Hawk jet is used by both the Royal Navy and Royal Air Force.
It is operational in two very distinct variants, the Hawk T Mk1 (and very similar Mk1A) and T Mk2.
RAF and Royal Navy Hawk T1 flying operations have been temporarily paused, while an investigation is carried out into a crash in Cornwall on Thursday.
The BAE Systems Hawk replaced the Gnat in 1980 and has become part of a comprehensive, world-class fast jet training system, according to the RAF.
Aviation expert John Sneller, from defence intelligence agency, Janes, said the Hawk is used by around 18 countries around the world and is "one of the most prolifically sold military aircraft that the UK has ever produced".
He added: "It's used in a number of different roles; it is very versatile.
"Overall, its safety record is excellent."
Like the T2, the T1 is a fully aerobatic, low-wing, transonic, two-seat training aircraft that is still used in several roles for the RAF.
However, it has been replaced as the Air Force's advanced fast jet pilot trainer by the new Hawk T2.
According to the Navy's website, the T1 has a top speed of more than 1,000kmph and a range of more than 2,250km.
The RAF Leeming-based 100 Squadron, flies the Hawk T1 in the 'aggressor' role, simulating enemy forces and providing essential training to the RAF front-line units.
In the Close Air Support training role, it can carry up to eight 3kg practice bombs.
It is also capable of undertaking a war role.
The T1 is also used by the Red Arrows and the Navy's 736 Naval Air Squadron, based in Cornwall, whose jets are marked with a distinctive lightning bolt.
The aircraft that crashed near Helston in Cornwall, prompting Hawk T1 operations to be temporarily paused, was from the squadron.
Equipped with the aircraft, 736 Naval Air Squadron's primary role is to provide simulated ship attacks for Navy and NATO units in the run-up to deployment.
They also use their jets to replicate the threats from enemy fighter aircraft and high-speed sea-skimming missiles.
In the Defence Command Paper published on 23 March, it was confirmed the Hawk T1 is among the British aircraft set to be retired in the coming years.
In 2004, the Ministry of Defence (MOD) contracted 24 examples of the RAF-specific Hawk Mk128, known in service as the Hawk T Mk2.
This model has replaced the Mk1/1A in the flying training role.
The T2 is based at RAF Valley on Anglesey and flies with IV Squadron and XXV (Fighter) Squadron, which provides advanced fast jet training (AFJT) to RAF and Royal Navy student pilots.
The aircraft has a glass cockpit and avionics suite to provide a realistic advanced fast jet training platform.
The on board simulation capability also enables air-to-ground 'weapon drops', realistic electronic warfare training against surface-to-air missile systems and other complex operational scenarios.
Hawk T2 Stats
Powerplant: one 6,500lb st (28.91kN) Rolls-Royce/Turbomeca Adour Mk 951 turbofan
Length: 40ft 9in (12.43m)
Height: 13ft 1in (3.98m)
Wingspan: 32ft 7in (9.94m)
Wing area: 179.64sqft (16.70m2)
Maximum take-off weight: 20,000lb (9,100kg)
Cover image: RAF.