During World War II he was commissioned to carry out specialised photographic work for the intelligence services in the Middle East.
After the War Quinn worked for a short time in his family business while writing film stories on the side.
He also worked for the British Picture Corporation and Metro-Goldwyn-Mayer, for whom he co-scripted the spy thriller Operation Crossbow together with Emeric Pressburger and Ray Rigby, and scripted several documentaries.
In 1973, Quinn partially quit screenwriting and moved to the South of France with his wife and son to pursue a career as a novelist.
Despite lukewarm reviews,[2][3] the first and the last were dramatised as part of Thames Television's suspense series Armchair Thriller, in 1978 and 1980 respectively.