239 Squadron RAF was formed from No 418 (Coastal reconnaissance) Flight at Torquay, on 20 August 1918, and was equipped with the Short 184, flying anti-submarine patrols with them until the Armistice.

The squadron began with Westland Lysanders, and then later re-equipped with Curtiss Tomahawks and Hawker Hurricanes.

The squadron converted to North American P-51 Mustangs in May 1942 and began ground attack and reconnaissance operations over Northern France, which lasted till August 1943, the squadron also taking part in the air cover during the Dieppe Raid.

[2] In September 1943 the squadron moved to RAF Ayr to train as a night fighter unit, and re-equipped with the de Havilland Mosquito.

100 (Bomber Support) Group, participating in night time operations against enemy fighters.