[1] As a screenwriter, he is notable for his collaborations with director Martin Scorsese, particularly The Age of Innocence[2] and Gangs of New York[3] — a screenplay he started working on in 1976 — as well as Kathryn Bigelow's Strange Days.
Cocks and Scorsese approached author Philip K. Dick in 1969 for an adaptation of his 1968 novel Do Androids Dream of Electric Sheep?
Though the duo never optioned the book, it was later developed into the movie Blade Runner by screenwriter Hampton Fancher and director Ridley Scott.
[5] Under the pseudonym "Joseph P. Gillis", Cocks and filmmaker Brian De Palma wrote a spec script for the crime drama television series Columbo in 1973.
[6] De Palma and Cocks did however contribute to the writing of the narrative crawl that opens the 1977 film Star Wars.