To play the disenchanted spy hunter at the centre of Tinker Tailor Soldier Spy, Gary Oldman went back to the classic novel and used its author, John le Carré, as a template.

“It was a rare occasion,” Gary Oldman says of the way he landed the role of spy hunter George Smiley in Working Title Films and StudioCanal’s Tinker Tailor Soldier Spy. “Normally you’re one of 10 people on a list, but I believe it was Tim Bevan [of Working Title] who said, ‘What about Gary Oldman?’ From that moment, they become obsessed and they only see you in the part, which was lucky for me.

“I didn’t say yes immediately because the ghost of Alec Guinness was hovering and I remember the series very well,” the 53-year-old UK actor says, in reference to the 1979 BBC TV adaptation of John le Carré’s espionage masterpiece. “He was such a beloved actor and had taken an iconic literary character and given him a face, so that was a bit daunting. Then I thought, well, actors play classical roles and there are other King Lears and Othellos and Hamlets, and here’s the chance to do a slightly new interpretation of it. So I approached it as if someone had offered me a classical role that had been played by many actors.”

In this regard Oldman, who is yet to earn Oscar and Golden Globe nominations despite a spirited body of work that includes Prick Up Your Ears, Leon, Dracula and Immortal Beloved, received some help. There was a first-rate screenplay from the late Bridget O’Connor and her husband Peter Straughan, a formidable troupe of UK acting talent and the involvement of Swedish director Tomas Alfredson, making his English-language debut after Let The Right One In.

Another significant asset in building the “disenchanted romantic”, as Oldman describes Smiley, was le Carré himself. The former British intelligence officer’s fiction is regarded as the gold standard of UK espionage writing, yet he was not precious about his work. “His brief was, ‘Look, the book is there. It exists. The TV series exists. Take this book and apply your imagination. Make it its own thing.’”

The result is a perfect companion piece to the TV series. Oldman, who in recent years has given delicious restraint where once there was unbridled exuberance, delivers a younger, steelier Smiley as he constructs a trap for a mole in the British secret service.

“I thought because [the story] was about loyalty and the loss of love, and friendship and betrayal, it would be an interesting time for it, especially [considering] our history involving Saddam Hussein and the hunt for weapons of mass destruction. The fear that engendered reminds you of the Cold War, when there was this dread of nuclear annihilation. Above and beyond the politics and its setting against the backdrop of the Cold War, the book has enjoyed longevity because it’s about people and character, and the fight for ideals.”

To become Smiley, Oldman steered clear of Guinness’ footprint and made a deliberate choice not to revisit the TV series. “I have the advantage of having this wonderful book — the three books, in fact, that make up the Karla Trilogy — and I didn’t work much outside the book. It was a remarkable screenplay. Le Carré said we managed to turn a cow into an Oxo cube. So I had the book, I had the script and I had access to John if I needed it. All the clues about who Smiley is are there — if you were ever in doubt, you went back to the source material.”

‘I just listened and watched’

Oldman visited le Carré, turning the observer into the observed. “We went to his lovely house in Hampstead and sat around and I asked him questions,” Oldman says. “He is a wonderful raconteur and does great impersonations. I just listened and watched him. I was looking for a voice to Smiley and there he was.

“I used John as a springboard, a template. You begin with an impersonation and as you work on it you get further away. The DNA of the whole thing was here. He’s got a similar background. He was a spy. He talked about Smiley and said it was like being with an old pal when he was writing the books. He’d jot down ideas when he was travelling.”

When production began at an abandoned army barracks in north London in autumn 2010, Oldman was ready to use the astonishing cast to his advantage. “It’s slightly easier for an actor when the book describes him as one of the smartest men in England. When everyone around you treats you with a slight reverence, they also do a great deal of the work for you. I have to do very little, for example, in the scene with [Tom Hardy’s character] Ricky Tarr. I could sit back a little.”

That’s not to say Oldman took anything for granted in such esteemed company. He confesses to being “like a fanboy” around John Hurt, who plays Control, the gruff, ailing spy chief who enlists Smiley to clean house at the British intelligence hub known as the Circus. “I was rather nervous to meet him on the first day… He didn’t disappoint.”

Oldman was also impressed by Colin Firth, bristling with animal magnetism and lethal ambition as senior intelligence officer Bill Haydon. So much so that the pair are mooting with Alfredson an undisclosed passion project Oldman says he has wanted to do for years. “In Colin I’ve found the guy to do it with.”

Their on-screen compatibility in Tinker Tailor Soldier Spy works like a subtle charm: Haydon’s somewhat flamboyant demeanour daubs the sombre 1970s milieu with splashes of colour, yet he never overwhelms his compatriot. If Haydon is the Circus’ perceived star, Smiley is the anti-star, sucking everyone towards him with an egoless gravity.

“George has a mask and there are things going on underneath, but he has this remarkable poker face,” Oldman says. “There’s a stillness to him that spoke to me and I think it did to Alec as well. It’s like the saying about how a king doesn’t have to shout — people come to him. There’s a description by [Smiley’s wife] Ann in the book where she says it’s as if he can lower his body temperature and he becomes like a swift. That was a big thing I locked onto.”

Oldman reserves special praise for Alfredson. “He is an original piece. You have seen it in the movie. I don’t know of anyone who would use [Charles Trenet song] La Mer for the end. That tells you how he thinks and approaches material. Apart from being a really nice fellow, he’s also a writer and an established comedian. He brings a lot of humour to the work. Even though the film is taut and austere, between the scenes we had some laughs. He’s a total original and a true artist. He reminded me of Alfonso Cuaron — they’re in the same orbit, the same sensitivity.”

There is talk of making a sequel, Smiley’s People. “I would love that,” Oldman says. “I miss George.” For now, though, there is Tinker Tailor Soldier Spy and le Carré for one appears to be glad about that. “I ran into John at a screening and I said, ‘So, what do you think?’ He said, ‘I’m chuffed as fuck.’ That’s praise indeed from the great man.”