THE ACTING profession has a way of turning its young tyros into harmless, tweedy national treasures. We won’t name names. But, without too much pondering, you can think of a few theatrical knights who – once fanged maniacs – now seem a little too at home in the gentleman’s club.

John Hurt is not such a figure. True, he has given up the booze. Queen Elizabeth II has put a CBE his way. But, though now as crinkled as a sultana, he looks and sounds very much like the chap who turned heads with early performances in Midnight Express, Alienand I, Claudius.(Come to think of it, he was always quite crinkled.) Now resident in London, he has just made a trip to the butcher's and is contemplating a nice meal with his wife and two sons.

“Mmm! Lamb shanks,” he says with glee. “One of my sons is a meat-eater and the other is a vegetarian. We’re going to have lamb shanks and my wife and son are going to have mushroom risotto. Or, as they say in the States, ‘riz-oh-toe’. Ha ha!”

Hurt turns up this week in Tomas Alfredson's superb adaptation of John le Carré's peerless espionage novel Tinker, Tailor, Soldier, Spy. Now a sprightly 71, he plays the ageing, wheezing head of the British secret service. Featuring Gary Oldman as George Smiley, the former deputy chief, summoned back to uncover a Russian mole, the complex, sombre film makes no concessions to audiences raised on the chaos of Bourne or the glamour of Bond.

“It was not a well-paid job,” he says. “But nobody is complaining. If it does terrifically well then we’ll get a bit of money back from the back end. Middle-budget pictures are in a difficult position now. There is a real void there. We hope this will put some bang into that void.” I was going to ask how the business has changed since he started out. I guess he’s already started to answer that question.

“Yes, that is the main change. The thinking has become overloaded towards the blockbuster. People think it’s not worth making a film unless it can make $800 million. Well, a film like this just can’t make that kind of money.”

John Hurt was, in many ways, an unlikely individual to turn up before the movie camera. Born in Derbyshire, he is the son of a clergyman and a mother who, he always believed, might have made a decent actor. One of his brothers, after converting to the Catholic faith, became a monk at Glenstal Abbey in Co Limerick. He had early ambitions to become a painter and attended St Martin’s Art College in London for a spell.

One lazily assumes that his parents, being church folk, must have disapproved of him running away to join the circus. A famously articulate fellow, he could surely have made it into a good university.

“Well, I was brought up in the days when you took notice of what your parents said,” he explains. “You didn’t turn round and say: ‘Piss off!’ My parents loved the theatre. What they couldn’t understand was the idea of one of their own being on stage. Which is odd. You’d have thought that, being a clergyman, he would understand what it was like to be apart from the crowd.”

Would he have made a good vicar? There is an element of performance in the job. “I would have made a perfectly good clergyman if I could have believed in it,” he says with a mild flourish of outrage. “From the age of 16, I just couldn’t understand how anybody could believe in all that. It baffled me. But I didn’t talk about that with my father. Crucial areas like that were just not talked about.”

He admits that art college in the late 1950s was an exciting place to be. While he was painting in St Martins, John Lennon – an exact contemporary – was getting a similar education at the Liverpool College of Art. But something else was nagging away at him. He uses an interesting word when discussing his eventual decision to switch to the Royal Academy of Dramatic Art (Rada). He says that certain “traumas” came to their conclusion. Why “traumas”? “Because I was painting and enjoying painting. But they were slightly traumatic years because, every now and then, I’d see something on the television and it would tear me to pieces. I just knew that that’s where I should be.”

Happily, his grant quickly running out, he managed to secure a scholarship to Rada. Like everyone in the profession, he struggled for a few years, but, by the close of the 1960s, he had secured a few very decent film roles.

He played Richard Rich in A Man for All Seasons. He was terrific as the doomed Timothy Evans in the undervalued 10 Rillington Place. It was, however, television that secured Hurt's fame.

In 1975, he played Quentin Crisp – self-proclaimed "stately homo of England" – in the BBC's (for once the cliche is accurate) ground-breaking production of The Naked Civil Servant.That show also made Crisp himself something of a celebrity. "I used to see him every time I went to New York," Hurt says. "But Quentin never let people very close to him. You'd never call Quentin a close friend. He was more of a guru. And you don't become friends with a guru."

Readers of a certain age will also remember him as Caligula in the BBC's mighty version of Robert Graves's I, Claudius. Notwithstanding that naughty film starring Malcolm McDowell, his is the face that most often springs to mind when mention is made of the grossly decadent emperor.

"Really? Oh, dear. Well God help us if I actually was him. I often quote that part when I hear those method actors say: 'Oh, I can't relate to that.' It's funny how I do an American accent when I say that. But they usually are American. How could you approach Caligula if you can't 'relate' to something really rather simple? If it's out of your experience you can't play it? Nonsense." This is an interesting comment. Hurt has always come across as an impressively natural actor. Those performers who furiously decry the method are, quite often, the same people who most enjoy the taste of theatrical scenery. But Hurt's performances have always been insidious, modulated and reactive. This, perhaps, explains why he works so effectively before the camera's magnifying eye. That talent was on display in such classics as Alienand The Elephant Man. He received an Oscar nomination for that last film, but he never took the plunge and moved to Los Angeles. He would surely have found work there.

“It was suggested to me. But it wasn’t the tradition that I came out of. I never thought of becoming a star. We wanted to act. The only actor I knew who said he wanted to be a star right from the beginning was Mike Caine. Mike’s dream was always to be a movie star. We all thought: ‘Mike wants to be a star. God bless him.’ But he got all of it.”

If the papers are to be believed, John has had quite a busy private life. Married four times, he has long been saddled with the unwanted “hellraiser” tag. Resident in Ireland for quite some time, he was occasionally photographed in a state of apparent alcoholic confusion. When the issue is raised, he issues a good-natured sigh.

“All that was a little unfair,” he says. “The problem was I just didn’t conceal it well enough. All that was just of the period. Everyone drank a lot then. It was the way of the world. You’d do a TV interview and have a drink and a cigarette with you. That gives you a sense of how things have changed. These days, if you order a glass of wine with your meal in America they consider you an alcoholic.” So why did he give it up? “Just for my own health and sanity. No, I don’t miss it at all.”

He moved back to England a few years ago – "for a few personal reasons" – but admits that Ireland is still a very important place for him. His sons regard themselves, at least in part, as being Irish and, in a recent television series, Hurt seemed to express a belief that he himself was from Hibernian stock. In a 2007 episode of Who Do You Think You Are?, the BBC's genealogy show, he was presented as being very disappointed that he was not related to the Anglo-Irish nobility.

“I was very disappointed with the programme,” he groans. “I was very silly. I should have realised that, of course, it’s just a kind of upmarket reality television.” He claims he was driven by a belief – or a hope – that he was related to his great pal Gareth Browne, the Guinness heir.

“The name ‘Browne’ comes into my family. And I wanted to prove Gareth was a cousin. They thought I was trying to establish some aristocratic background. I was never interested in that. They don’t explore what they don’t want to explore.” Surely a man of his experience should have realised what canny film-makers can get up to in the editing suite? “Yes, yes, yes. I know. Anyway, if I am asked what I regret in life that’s one thing.” Just that? “Well, I don’t regret many things in life.”

The key John Hurt roles

The Naked Civil Servant(1975)

he BBC's adaptation of Quentin Crisp's memoir of gay life in mid-20th century England dragged TV representations of homosexuality away from the evasions of Larry Grayson. Hurt won a Bafta for the performance and, in 2009, returned to the role for An Englishman in New York.

Alien(1979)

Hurt was drafted into the role of Kane – the executive officer who gives bloody birth to the titular antagonist – when Jon Finch fell ill. Hurt confirms that the story about the cast not knowing his chest was going to explode is sheer nonsense. “They’d read the script.”

The Elephant Man(1980)

In arguably his finest performance, Hurt, buried beneath wads of rubber, made something painfully humane of the Victorian neurofibromatosis patient. “He was always odd,” Hurt says affectionately of director David Lynch.

The Proposition(2005)

In recent years Hurt has found it hard to secure lead roles, but he is a consistently brilliant supporting player. A case in point is Jellon Lamb, the grizzled bounty hunter in John Hillcoat’s excellent Australian western.

Melancholia(2011)

Two weeks after Tinker, Tailoropens, Hurt can be seen as Dexter, jovial father to sisters played by Kirsten Dunst and Charlotte Gainsbourg, in the latest oddly beautiful film from Lars von Trier. Hurt previously narrated the director's Dogville and Manderlay.