Best Actor Oscar winner Colin Firth says he was all too happy to step aside and take a supporting actor role for his “meaty” new part in “Tinker, Tailor, Soldier, Spy.” “It was great to have something that was meaty enough to get my teeth into, but let other people do the heavy lifting.” Firth told journalists at the Venice Film Festival Monday. “It's basically all I did last year and it suited me very well.” Firth — who won the Oscar for “The King's Speech” and was nominated for the same award for “A Single Man” — plays the calm, collected intelligence agent Bill Haydon, a counterpoint character to the films lead Gary Oldman, playing the main character, retired spy George Smiley. “Tinker, Tailor, Soldier, Spy,” directed by Tomas Alfredson — the Swedish director of 2008 vampire film “Let the Right One In” — is among entries vying for the top “Golden Lion” prize at the festival's conclusion this Saturday. Alfredson's interpretation of the John Le Carre Cold War spy yarn is a slow-brewing, elegant retelling of the classic novel. But will audiences fall for a subtly paced spy drama that unravels to reveal betrayal and retribution without the sexy antics of a James Bond film, or the action packed scenes of a “Bourne Identity?” “There is a tendency to underestimate audiences,” Firth said at a news conference. “People don't just want ‘slash and burn' — so I am optimistic about (the film) having an enormous audience.” Audiences may be surprised that Firth opted for a supporting role — and less on screen time — given his domination of the screen as Britain's King George VI in “The King's Speech.” Likewise, in “A Single Man” in 2009, Oldman's mannered performance as Smiley offers an anchor in this complex whodunit that focuses on the inner-workings of the UK's elite M16 intelligence agency, which needs to cover up — or prove — the existence of a highly placed Soviet mole. London provides most of the thriller's elegant ambiance, where trench coat-sporting intelligence staff sip tea or scotch, send numerically coded messages and sneak files out of archives. The movie also travels to the Turkish city of Istanbul for key scenes.