David Threlfall: Frank, in more than one sense

He has won a following which may, at last, lodge him into the public consciousness

In the three decades since his 1977 appearance in Scum, Alan Clarke's brutal exposé of life in borstal, the actor David Threlfall has played everyone from outcasts to royalty. He is feted among colleagues for a meticulous attention to detail and an almost unnerving capacity to get inside the characters he plays. But he has never been a star.

Until now. For in the creation of the feckless drunken Frank Gallagher in Channel 4's acclaimed series Shameless, which returns on Tuesday, he has won a following which may, at last, lodge him in the public consciousness. It is a mark of Threlfall's acknowledged brilliance that despite being in almost every way repellent, audiences have warmed to Gallagher and his wayward family, as conceived by the writer Paul Abbott, on a Manchester housing estate. The drama's success is such that after this series, the fourth, an extended series is planned for next year and Channel 4 is building a permanent set for filming.

And in a reflection of the pivotal importance of Frank Gallagher to the award-winning show, he moves centre-stage in the new series, back into the family home. For Francis Hopkinson, Channel 4's commissioning editor for drama, Threlfall's Frank has become the linchpin of the drama. "Oddly, he has become the thing that people feel so affectionate about," he says. "He conveys an intelligence and a warmth and humanity somehow even though Frank's a drunken, drug-taking bigamist and absentee father. He sounds terrible but you kind of love the fact that he is unrepentantly who he is."

With each series, more and more viewers have fallen for Frank, and David Threlfall's profile has soared likewise. But casting directors have known him as a performer to be trusted for decades. His CV stretches from Edgar to Laurence Olivier's King Lear through Paradise Postponed, John Mortimer's tale of scheming Tory Leslie Titmuss, to films including Master and Commander and Conspiracy, the Emmy award-winning drama in which he co-starred with Kenneth Branagh and Colin Firth.

Dominic Dromgoole, the artistic director of the Globe, considers him the next Alec Guinness. "He's a funny mixture of a star actor and a character actor," he says. "He takes character acting to such super high-definition accuracy that it becomes a star performance in itself. He's brilliant."The playwright David Edgar praises his "capacity to completely inhabit a character and do it boldly, but also to do it with subtlety and deftness and wit". Paul Abbott, the writer of Shameless, now considers him a mate. "He's great. He's very funny, extremely sharp and witty - but not in the same way that he plays Frank."

David Threlfall was born in Burnage, Manchester, in 1953, the son of a builder who originally hoped his offspring would carry on the family business. But Threlfall was smitten by the stage bug after an early appearance in a school play and went on to study drama at Manchester Polytechnic. Afterwards, he walked straight into work with the Hull Truck Theatre Company, the director Mike Leigh and the writer-director Les Blair.

He then joined the Royal Shakespeare Company where he was to win the first great reviews of his career as Smike, the abused inmate of Dotheboys Hall in the landmark production of Charles Dickens's novel Nicholas Nickleby. It ran for five sell-out seasons over two years and transferred to Broadway where Threlfall was nominated for a Tony award as well as an Emmy for a TV version.

David Edgar, who wrote the adaptation, says Threlfall's Smike was one of the two greatest performances in any of his plays (alongside Edward Petherbridge, also in Nickleby). "It was absolutely breathtaking," he recalls.

Edgar expanded on the role from the book, because over a long rehearsal period he could see what Threlfall would bring to it. "I don't think I would have written so much had I not been convinced that [Smike's] death would be the moment of complete surrender by the audience. The fluttering of Kleenex was the flag of surrender. It was was always desperately moving. I was never immune to it. But he was also quite witty."

Part of the success lay in the actor's physical commitment to the role. "He had lots of padding for when he was beaten,"David Edgar recalls, "but we were quite worried because on occasions enthusiastic Squeers [the school head] missed. And he very accurately reproduced the symptoms of rickets."

The success might have been expected to catapult Threlfall to stardom. But Dominic Dromgoole, who directed him in 2005 in the Frank McGuinness play Someone Who'll Watch Over Me, says he was never ambitious or greedy for fame. "He's flowed in and out of our consciousness, but he's not pursued it. He's never been one for sitcoms or television series based on his own charm or cop shows or adverts. That's just not to his taste."

Instead, his career since those first dizzying years with the RSC has been a steady flow of theatre, film and television with only one dry patch where he scarcely worked for a couple of years. "My motivation was always a simple one," he said once. "To keep working." He has starred in seasons at the Royal Exchange in his home city and played Bolingbroke in Richard II with Fiona Shaw at the National Theatre. He played the title role in Hamlet for the Oxford Stage Company and worked with Sir Peter Hall on Ibsen's The Wild Duck. In 2001, he won rave reviews for his performance in Joe Penhall's psychiatric drama Blue/Orange.

On television, he has appeared in dramas including the Mary Wesley adaptation Jumping the Queue, Nightingales alongside Robert Lindsay, and Diana: Her True Story, where he played Prince Charles. Last year, he was a scene-stealer as Charles's dad, Prince Philip, in The Queen's Sister, the Channel 4 drama about Princess Margaret.

For the McGuinness play, about a Brian Keenan/John McCarthy-like hostage situation in the Middle East, Threlfall spent a couple of days walking around Peterborough and taking photographs because that was where his character was from. He read everything he could about the hostage experience. "He's very assiduous," Dromgoole says. "He's also got a wonderful understanding and take on different sorts of Englishness. He can do the ambitious young Tory politician Titmuss; he can do Smike; he can do the character in Shameless and he can do a character like the university lecturer mummy's boy in Someone Who'll Watch Over Me and all of them are equally accurate and equally perceptive and full of insight."

Even so, his performance in Shameless appears to have transformed his professional life. In 2003, the year that Channel 4 phoned, he played the lead - brilliantly - in John Osborne's The Entertainer at the Derby Playhouse. "I think they would be lucky to get him now," notes one showbusiness insider.

Threlfall himself acknowledged, in a rare interview a couple of years ago, that it was "great" he was starting to be noticed and that opportunities were flooding in, but insisted: "My feet are very much on the ground. People say I'm famous these days, that Frank Gallagher is iconic, and that's good. Of course it's good. But it's not like I've suddenly appeared out of, I don't know, the ether."

And perhaps a happy marriage to the Sarajevo-born actress Brana Bajic, two children and Shameless's success have helped to smooth a few rough edges. Early in his career, there were hints he was not always easy to deal with. Mike Leigh, who directed him in 1978's The Kiss of Death, said he had "a slightly surreal streak that sometimes gets in the way", and the director Trevor Nunn said he could be "a handful".

Yet Paul Abbott, the writer of Shameless, claims Threlfall is a joy on set, where he is now directing episodes as well. "He's really constructive and helpful on the building of those tiny, tiny things that you have to attend to," Abbott says. "He simply wants to get stuff right. He will ask more questions than a lot of people - if he needs to."

Abbott sees him as "axial" to the series but has no worries that success will spoil him. Although Abbott believes Threlfall's relative anonymity has helped him to produce his good work, that will not change. "A lot of people don't even recognise him. My sister didn't when she was standing next to him. And every time I see him playing a part, I forget that I know him. He can play anybody."

'Shameless' returns to Channel 4 on Tuesday at 10pm

A Life in Brief

BORN 12 October, 1953, Manchester

EDUCATION Manchester Polytechnic School of Theatre

CAREER Joined the Hull Truck Theatre Company, then the Royal Shakespeare Company, 1977-1979. In 1986, performed a season at the Royal Exchange, Manchester, and returned in 1994 and 1999. Other theatre work includes Richard II and Tartuffe at the National Theatre in 1995. Television work includes Scum in 1977,King Lear in 1984, Paradise Postponed in 1986, Diana: Her True Story in 1993 and The Queen's Sister in 2005. There have been three series of Shameless since 2004. Films include Master and Commander (2003) and Conspiracy (2001).

HE SAYS "I think on a good day there is not a lot I can't do. But nothing has changed in my life, not really. I'm still bobbing along, like I always have."

THEY SAY "David manages to make the ugly beautiful and has a brilliant knack of seeming to have thought about every line as if it were on the spur of the moment." Gerald Faber, executive producer, Shameless