 He invented the multi-track mixing desk.During his lifetime he served as a Spitfire pilot in the RAF during World War II, became one of the first pioneers of electronic music, and co-wrote one of the first books on UFOs, "Flying Saucers Have Landed" (1953), with writer and UFO contactee George Adamski.Leslie is probably most famous for punching theatre critic Bernard Levin in front of eleven million viewers during an edition of the live satirical TV show "That Was The Week That Was" in 1962.