The Royal Air Force's 1930s expansion plan included a requirement for a station to provide anti-submarine and anti-shipping patrols off the South-west coast of England.

[1] Five widely dispersed cottages, two houses and portions of two farms were acquired by compulsory purchase; the village of St Eval was completely demolished in order to build the airfield.

In June 1940 St Eval became a Fighter Command sector headquarters during the Battle of Britain and Supermarine Spitfires were stationed there.

St Eval was equipped with a green box barrage rocket device which sent a steel wire curtain into the air to descend on parachutes.

On 6 April 1941 a small force of Beauforts from 22 Squadron, operating on detachment from St Eval, launched an attack on the German battleship Gneisenau in Brest harbour.

Both of these squadrons were reassigned to Port Lyautey in French Morocco in March 1943 to shore up scanty Allied anti-submarine defences in the Atlantic approaches to the Straits of Gibraltar.

Also, over the long term, the Allies wanted to increase air anti-submarine patrols and convoy coverage to secure their preparations for the impending Tunisian offensive and the subsequent invasion of Sicily.

After that time the Germans avoided surfacing during daylight and adopted a policy of evasion, but the group continued its patrols, often engaging Luftwaffe fighter interceptor aircraft.

On 20 June 1943, in the Bay of Biscay, one of a pair of Whitleys operated by 10 OTU from St. Eval was shot down while attacking a submarine believed to be the Barbarigo, of the Italian navy.

The Whitley caught fire which cooked the depth charges and caused a massive explosion and the loss of both the aircraft and crews.

[10] The importance of St Eval was such that it was given a FIDO installation in early 1944 for dispersal of fog around the runway so that aircraft could land safely.

This force flew thousands of hours of patrols each month and was rewarded with a number of sightings, many of which were converted into attacks, with at least three confirmed U-boat kills in June alone.

It was also a site for diversions with a number of military and commercial aircraft making use of St Eval due to bad weather at their destination airfield.