The trailer for Tinker Tailor Soldier Spy, the adaptation of John Le Carre’s best-selling spy novel, begins with the line, “There is a mole right at the top of the circus.” Anyone who has read the book, or is familiar with the jargon of the British clandestine services, knows that “Circus” is the slang term for the highest levels of the British Intelligence Services. For everyone else, it sounds like this menacing, sleek thriller might be about a tiny rodent stuck way up in a big top. It is not about a tiny rodent stuck way up in a big top. It is about spy business, and the particular spy business of tracking down a Russian plant in British counterintelligence during the Cold War. Dashing British men, including Colin Firth and Tom Hardy, conduct espionage — travel the world, use guns, stand in shadows — while Gary Oldman, who has the lead role as George Smiley, tries to identify the mole (who totally doesn’t wear a top hat and a little red jacket and have the skills to get shot out of a cannon), all while menacing violins ratchet up the tension.