Bell made his film debut in Joseph Losey's "The Concrete Jungle/The Criminal" (1960) but his first film impact came with Bryan Forbes' "The L-Shaped Room" (1962). Bell starred as an out-of-work writer who romances a pregnant Leslie Caron. His other film credits include "Payroll/I Promised to Pay" (1961), as a cat burglar in "He Who Rides a Tiger" (1966), "Lock Up Your Daughters" (1969) and "Straight on Till Morning" (1974). Bell subsequently appeared as Emily Lloyd's sleazy lover in "Wish You Were Here" (1987), as a petty thief in "The Krays" (1990), opposite Sir John Gielgud in "Prospero's Books' (1991) and as the head of a family that offers shelter to a troubled young woman in the period drama "Feast of July" (1995).
Bell has been active in British TV from the 1960s, appearing in series and specials, and was seen worldwide as Adolph Eichmann in the miniseries "Holocaust". He appeared in two adaptations of D. H. Lawrence novels shown on PBS in the US: "Sons and Lovers" (1983) and "The Rainbow" (1989). Fans of "Prime Suspect" (PBS, 1992) will recognize Bell as Sergeant Bill Otley, the cop who first rebels against, but later comes to respect Jane Tennison (Helen Mirren). He reprised the role in the second sequel, "Prime Suspect 3" (PBS, 1994).