Awarded: June 1945

Blazon: A Mosquito proper

Link: The badge symbolises the type of aircraft used by the unit. The motto appears not to be a phrase used in classical times, but is said to be an abbreviation of a phrase used by Plato originally to describe an essential condition.

Motto: Sine qua non – Indispensible

History: Formed at Leuchars on 19 October 1942; disbanded at Wyton on 31 March 1956

Battle Honours: No Standard

Sponsored by Just Wood and dedicated to all who served with No 540 Squadron