Sid James agreed to play a minor role in exchange for a case of Scotch whisky.
Second of three Charles Vine spy movies. The first was Secret service (1965) and the third and final film was O.K. Yevtushenko (1967). Actor Tom Adams played Vine in all three.
The production received the assistance of the Royal Air Force (RAF) who allowed a number of scenes to be shot at the RAF Biggin Hill Aerodrome.
The film's MacGuffin was the Spurium Apparatus which was a device that allowed a plane to fly fueled by nuclear power.