Gates was involved in stage management by the early 1950s, and began scriptwriting in his spare time.
[1] He wrote, co-wrote or worked on the screenplays for Barbarella (1968), Danger: Diabolik (1968), The Vampire Lovers (1970), Fright (1971), Lust for a Vampire (1971), Twins of Evil (1971), The Love Box (1972), The Optimists of Nine Elms (1973), The Sex Thief (1973) and Intimate Games (1976).
Turning to the stage again in the mid-1970s, Gates wrote Who Saw Him Die?, Aurelia and Who Killed Agatha Christie?
[3] A lifelong trade unionist, Gates became the President of the Association of Cinematograph Television and Allied Technicians and supported its merger with the Broadcasting and Entertainment Trades Alliance which formed the Broadcasting, Entertainment, Cinematograph and Theatre Union (BECTU), of which he served as vice president until 2004.
A controversial figure, he twice took his union to court, using legislation passed by the Conservative Party in the 1980s.