Jacqueline Durran made headlines four years ago with the emerald-green evening dress she designed for Keira Knightley to wear in Atonement. It is unlikely the immaculately tailored suits worn by the agents in Tinker Tailor Soldier Spy will have the same impact, but working on the film was an unusual challenge for the Oscar-nominated costume designer; the clothes are just as vital to setting the emotional tone of the film as Knightley's gown was in the adaptation of Ian McEwan's novel. "You just had to pile on the detail to get any kind of message across," she says. "With menswear it is all about detail, rather than making a splash with a big dress."
Watching the film you are able to pick up hints about the characters from their choice of suit. Gary Oldman's sombre George Smiley wears a dark-grey three-piece in the style of the 1950s and a plain Aquascutum raincoat from the same era, the latter inspired by a photograph of Graham Greene given to Durran by director Tomas Alfredson. Office dandy Bill Haydon (Colin Firth) sports a raffish suit made by Savile Row tailors Huntsman, ginger desert boots and bright red socks. "Le Carré gave me some notes where he pointed out that some of the men were quite eccentric dressers," she says.
Durran looked at contemporary images of politicians and civil servants to get an idea of how men of a certain age and status dressed. Anxious to avoid the cliches of early-1970s fashion, such as loud colours and bold patterns that would have been out of place in Alfredson's elegant, wintry film where sunlight is seldom seen, she also researched earlier decades for inspiration.
"I thought that lots of these middle-aged men had bought suits 10 or 15 years ago and stuck with them," she says. "I would look at a character and try to work out where they had bought their suit."
She decided that everything in the film could have been bought from shops within half a mile of Piccadilly in London: "Things from Savile Row, Jermyn Street, Fortnum & Mason, Burlington Arcade – one of those upper-middle-class shops that are never fashionable but always do a certain kind of clothing."
One of Durran's hardest tasks was finding the right pair of glasses for Smiley: "Glasses are incredibly important for actors. It is the only thing between them and the camera, so they have to feel right." The film-makers wanted to distance themselves from the pair worn by Alec Guinness in the acclaimed BBC series, but after 50 pairs they still had not found the perfect ones. Oldman eventually discovered them in Los Angeles, a thick-framed plastic set similar to the ones Guinness used 30 years earlier.
Tom Hardy, who plays field agent Ricki Tarr, has the most interesting wardrobe. In the novel the character is Australian, which encouraged Durran to give him a more expressive style: "He is out shooting people, so we wanted him to be this manly action person. The first person we turned to was Steve McQueen." Inspired by the classic photographs of the Hollywood star taken in the early 1960s by William Claxton, Durran put Hardy in "really straight cord trousers, preppy shirts, simple white short-sleeved T-shirts" and a classic Harrington jacket.
The MI6 office girls were also able to wear more colourful clothes, but again Durran did not turn to 1970s fashion for inspiration: "They were all middle-class girls who spent their weekends in the country. I wanted them to have an old establishment way of dressing. It was the classic English look. I was so happy when I could get someone in a long tartan skirt in the Christmas party scene."
In the end, though, Tinker Tailor Soldier Spy is all about men in suits. You increasingly notice the significance of what they are wearing as the film progresses, which is exactly as Durran intended. "I am doing Anna Karenina now [starring Keira Knightley] and I can tell you that people will notice her changes of costume more than they'll notice the suits, but when there is no one else in the film apart from the men in the suits then you do focus on them."