The prison sequences were filmed in the abandoned Kilmainham Jail in Dublin, which was also used for " The Italian Job" and " Mcvicar".
The year this film was released, Edward Woodward's series of "Callan" was drawing to a close.
"Sitting Target" was one of the first British films to be given an "X" certificate for its violence alone. In spite of that, the B.B.F.C required a few cuts to be made before allowing the film to be released.
Most fans agree that Oliver Reed was far better cast as a psychopathic gangster than Richard Burton from "Villain."