John Salmon was a famous British advertising executive and copywriter, one of the most prominent advertising men in the world in the 1960s and 1970s and the man who gave early breaks to (and served as mentor for) such later-eminent figures as Alan Parker and David Puttnam. He was also perhaps the closest friend of author Len Deighton - a friendship formed, not during Deighton's days in advertising, but earlier, when they were teenagers in the RAF a few years after World War II. When Deighton turned film producer to make the movie version of his own novel, "Only When I Larf", he hired Salmon to write the script (his only screen-writing credit on a feature film).