A 91 squadron was initially formed in September 1917 at RAF Spitalgate but had moved to Chattis Hill within the month to undertake Wireless Telegraphy training.

The new squadron was intended to be equipped with Sopwith Dolphins but never became operational in time and was moved to Lopscombe Corner and disbanded in July 1919.

Later in the year, now based at RAF West Malling, Kent and equipped with the faster Spitfire XIVs they were deployed to combat the V-1 flying-bomb attacks (Capitaine Jean Maridor was blown up in mid-air when he got in too close to shoot a V-1 down [2]).

In April 1945 the squadron relocated to East Anglia to carry out reconnaissance missions and searches for midget submarines off the coast of the Netherlands and Belgium.

After the war the Squadron moved to RAF Duxford and in October 1946 converted to Gloster Meteors.