It operated a mixture of aircraft, including seaplanes, Airco DH.9 bombers, and Sopwith Camel fighters, and was responsible for the defence of the Thames Estuary.

It reformed in October 1939, shortly after the outbreak of the Second World War, operating Bristol Blenheims from RAF Catterick.

Whilst it was intended to carry out shipping protection missions, it began to be used as a night fighter unit after becoming fully operational in February 1940; in October, it was moved to RAF Redhill, near London, and converted to the Bristol Beaufighter.

In September 1943 it operated a number of aircraft from Sicily, but moved back to the UK in January 1944 to join the newly forming Second Tactical Air Force in preparation for the invasion of Normandy.

It moved to bases in France in October 1944, returning to the UK after the end of hostilities in August 1945, and was disbanded in September 1946.