The Gnat was a small swept-wing British light fighter aircraft developed by Folland Aircraft. The Gnat was a two seater but also a single seat version was developed called the "Midge"which was a limited success but was sold to Finland. The Gnat was also flown extensively by the Indian Air Force including a single seat variant, called the "Ajeet". The two seat Gnat was the trainer variant.

The Midge first flew in 1955 and was of a simple design with a swept wing. It was kept small to reduce costs and to meet the 1952 Operational Requirement OR.303 calling for a lightweight fighter. The Royal Air Force lost interest in the fighter, but needed the Gnat as a two-seat trainer as step up for training towards particularly the English Electric Lightning. A more powerful Orpheus engine was installed and larger tail surfaces fitted. The inboard ailerons were also changed to outbound ailerons and conventional flaps. The prototype Gnat Trainer first flew on August 1959 from Chilbolton airfield. After a while, production orders were given for the RAF beginning of the nineteen-sixties.

The first production Gnat T.1 aircraft for the Royal Air Force were delivered in February 1962 to the Central Flying School at RAF Little Rissington. Over 100 aircraft were build by the Hawker Siddeley company, who had taken over Folland. The Gnat was also used a lot at RAF Valley, the major training base in the UK. In 1964, the Gnat was also used by the RAF aerobatic team Yellow Jacks, later to become the famous RED ARROWS. The Gnat went out of RAF service in 1978.

The Folland Gnat was developed as a reaction to the growing size, weight and cost of post WWII jet fighters. The Gnat was the creation of W.E.W. "Teddy" Petter, a British aircraft designer formerly of Westland Aircraft and English Electric; he was also the Chief Engineer of the Canberra and was instrumental in the conception of the massive (and expensive) Lightning fighter.

first prototype was built as a private venture and took to the air on 18th July 1955. Shortly thereafter, the Ministry of Supply ordered another six aircraft for evaluation. In 1958, the Gnat was a contender to replace the de Havilland Venom but lost to the Hunter, at which point the RAF lost interest in its procurement as a fighter. Petter reacted by modifying the design to meet the contemporary specification for an advanced two-seat trainer to replace the Vampire T11 and an initial contract was let for 14 pre-production aircraft. The prototype trainer first flew on 31st August 1959 after which orders followed in batches for 91 aircraft with the designation Gnat T1.

The first production machine entered service with the Central Flying School in February 1962 and deliveries to the prime user, No 4 Flying Training School, RAF Valley, began in November of that year. In 1963, a small group of 4 FTS instructors established an informal aerobatics team known as the Yellowjacks which, two years later, expanded into the official RAF aerobatics team, the Red Arrows.

Whilst the RAF utilised the Gnat solely as a trainer, the fighter version was purchased by Finland, which operated 13 aircraft between 1958 and 1978, and India, which equipped a total of 8 squadrons over the same period. Armed with 2 x 30 mm Aden cannon, it was during the Indo-Pakistani Wars of 1965 and 1971 that the Gnat fighter proved itself. Indeed, the soubriquet “Sabre Slayer” was well-earned by the number of victories achieved in air-to-air combat against the technically superior Canadair Sabre Mk 6. Such was the aircraft’s performance in these two wars, that in 1972 the Indian Air Force issued the requirement for a Gnat F2. Over 175 of these upgraded variants, known as the Ajeet, were built under licence by Hindustan Aeronautics Ltd with a further 40 being provided by Follands.

The Gnat T1 was also retired in 1978 on being replaced by the Hawk as the RAF’s advanced trainer with the Red Arrows switching over the following year. A total of 449 machines were built (including the Ajeet) and many survive today, including several airworthy versions in the UK and USA.