Edward Woodward became a household name as Callan, the cold-blooded Secret Service agent in the television series of the same name, which ran for seven years from the late 1960s. But he suffered from being too closely associated with the character and this affected his subsequent career.

Not until 1985 did he have a comparable success, this time on US television, in The Equalizer. As Robert McCall, a former CIA agent, Woodward may have looked older and greyer but he was happily back in the Callan mould.

Woodward's thoughtful and unflamboyant acting style was particularly suited to television, though he also appeared regularly in the theatre, where his work ranged from Shakespeare to pantomime, and he made several films. His pleasant tenor singing voice was heard in stage musicals, on TV variety shows and on more than a dozen records.

Edward Woodward was born in Croydon and grew up in South London. He studied at Kingston Commercial College, intending to become a journalist, but changed his mind and won a scholarship to the Royal Academy of Dramatic Arts. At 16 (he lied about his age), he was the academy's youngest student.

But he stayed only a year, and there followed a long apprenticeship in repertory companies in England and Scotland before his first West End appearance in 1955.

His first big personal success came in 1962, when he starred opposite Sheila Hancock in the West End comedy Rattle of a Simple Man by Charles Dyer.

Callan started in 1967, and Woodward's downbeat portrayal of the seedy, ruthless intelligence agent, who had been conceived by the writer James Mitchell as an antidote to the glamour of James Bond, caught the public imagination and drew huge audiences.

Woodward also caught the attention of Sir Laurence Olivier, who called him "one of the best actors in England" and signed him up for the National Theatre. Taking a substantial drop in salary, Woodward played Flamineo in The White Devil and the lead role in Cyrano de Bergerac.

When Callan ended in the early 1970s, Woodward went through a difficult period of professional adjustment as he tried to establish a new niche. At the same time, his private life hit the headlines when he left his wife and three children to live with a young actress, Michele Dotrice, the daughter of the actor Roy Dotrice. She became best known for her portrayal of Betty, the long-suffering wife of Frank Spencer, played by Michael Crawford, in the 1970s television sitcom Some Mothers Do 'Ave 'Em.

His film career began in 1964 with Becket. Although he was never a star on the big screen, he contributed effective character studies to a number of films, including Young Winston (1972) and Champions (1984). His strait-laced and devoutly Christian policeman investigating the case of a missing girl and Satanism on a Scottish island in The Wicker Man (1973) was a relishable performance.

But Woodward's best part was as Lieutenant Harry Morant in Breaker Morant (1979), an Australian army officer court-martialled for murdering prisoners during the Boer War. His rendering of the song 'Soldiers of the Queen' became a popular record.

In 1981 he was back as Callan in a single adventure, Wet Job, and he was still partly living in Callan's shadow when he was offered The Equalizer. The show ran for six seasons and during it, to his considerable surprise, Woodward was voted "sexiest man in the nation" by US TV viewers. He won a Golden Globe in 1987 for his role in the show. After living for some years in the US, he returned to England in 1990, fearing the effect of American violence on his young daughter.

He became a familiar face on British TV again, as the presenter of In Suspicious Circumstances, a series of dramatisations of real crimes, and as a dustman in the BBC comedy-drama Common as Muck.

In 1996 he suffered two serious heart attacks and underwent a triple bypass operation. After a previous attack nine years earlier, he had been ordered to give up smoking (he had smoked 100 cigarettes a day) but became dangerously overweight through a weakness for rich food.

The operation was successful, and he was soon able to resume his acting career. In 1998 he was cast in the role formerly taken by Gordon Jackson in a revival of the 1970s TV crimefighting series The Professionals.

In 2007 he had a part in the film Hot Fuzz. Last year he appeared in two episodes of the TV series The Bill, and earlier this year he played Tommy Clifford in six episodes of the BBC soap EastEnders, his last appearance.

However, he is due to be seen in the film A Congregation of Ghosts, in which he plays the Rev Frederick Densham, the real-life vicar of a remote village on Bodmin Moor who died in 1953 and returns to haunt those parishioners who ostracised him.

In addition to his albums of songs he also recorded three albums of poetry and 14 books on tape. He appeared more than once on The Good Old Days, BBC television's tribute to Victorian music hall.

Woodward was appointed OBE in 1978. He was voted Television Actor of the Year in 1969 and again in 1970, in which year he won the Bafta award for Best Actor for his portrayal of Callan.

Woodward's first marriage in 1952, to the actress Venetia Barratt, produced three children, who all became actors. In 1987 he was married to Michele Dotrice, with whom he had a daughter. They lived near Padstow in Cornwall. She and his four children survive him.

Woodward was suffering from several illnesses including pneumonia when he died on Monday, aged 79.

Irish Independent