George Sewell

Sewell, who has died of cancer at the age of 82, played a gangster who menaces Michael Caine in the classic British crime film Get Carter (1971). But he acquired his most dedicated fans after appearing in a live-action science-fiction series from the creator of Thunderbirds, playing Colonel Alec Freeman on UFO (1970-73).

The hard edge he brought to his characters was a result of his late entry into the acting profession and his previous experience as a merchant seaman, a street photographer and in various other jobs.

Born in the East End of London in 1924, Sewell left school at 14 and apprenticed as a printer, like his father. He enlisted in the RAF during the Second World War and spent eight years in the Merchant Navy and five years as a courier for a holiday company in England, before a chance meeting in a pub with actor Dudley Sutton led him to audition for the musical Fings Ain't Wot They Used T'Be.

Director Joan Littlewood preferred "real people" to classically trained actors. The musical was set in Soho, at the time a very seedy area of London, and Sewell played the first of many policemen. It opened in the West End in 1960, with a cast that also included Miriam Karlin, Barbara Windsor, Yootha Joyce and James Booth.

Sewell was 35 by this time. He did not consider himself an actor and expected to go back to being a travel courier when the run ended. However the show was a major success, Sewell spent two years with it and he subsequently became a member of Littlewood's repertory company.

He appeared in her musical Oh, What a Lovely War! in London in 1963 and on Broadway the following year, playing both Field Marshal Haig and the Kaiser. The roles were played by John Mills and Kenneth More respectively in the 1969 film.

Sewell was better known for his television work than his films, though his big-screen career got underway in 1963 with significant supporting roles in three films, Littlewood's Sparrows Can't Sing, This Sporting Life and the crime drama The Informers.

Over the next decade he worked steadily in theatre, television and film, appearing in further big-screen supporting roles in Kaleidoscope (1966), with Warren Beatty, Robbery (1967) and The Vengeance of She (1968). He once commented: "We all know great actors who have struggled, so I feel lucky I've made a good living."

UFO was a live-action sci-fi series, though the basic scenario of alien invaders and a secret defence organisation recalled Gerry Anderson's earlier puppet shows. ITV schedulers could not make up their mind if it was for adults or children - in some areas it went out late at night and in others it was broadcast on Saturday mornings.

It made little impression at the time, but has acquired a dedicated following on video and satellite television.

Sewell's standing among sci-fi fans was later enhanced when he appeared in the special 25th anniversary Doctor Who storyline Remembrance of the Daleks in 1988.

Special Branch elevated him to a starring role, as part of a double act in which he and Patrick Mower played police detectives. During his term with Special Branch Sewell featured on This Is Your Life and topped the ratings.

Years later Special Branch helped inspire The Detectives, on which Jasper Carrott and Robert Powell played two bumbling policemen with Sewell as their boss.

Although his most memorable television appearances were on cop shows and sci-fi, Sewell appeared in a wide range of programmes, including sitcoms.

In the Some Mothers Do 'Ave 'Em 1975 Christmas special he was a store Santa, with 25 years' experience, driven mad when Michael Crawford signs on as his pixie.

He played an ex-policeman on The Bill in 2005 and was in an episode of Casualty last year. He is survived by his wife and daughter.