To help get the word out about the impending Mission: Impossible – Fallout home video release, I had a chance to visit the International Spy Museum in Washington D.C., and speak with real-life former spies. Peter Earnest, a 35 year veteran of the Central Intelligence Agency, and Jonna Mendez, a former Chief of Disguise in the CIA’s Office of Technical Service, spoke with me about their careers in the spy trade, how they got into their line of work, and more.

But seeing as we care most about movies around here at /Film, I had to ask these real-life secret agents: what would an actual spy consider to be the most accurate spy movie? The answer probably isn’t too surprising: Tomas Alfredson‘s 2011 slow-burner Tinker Tailor Solider Spy.

Peter Earnest served 25 years as a case officer in the CIA’s Clandestine Service, running a wide range of “intelligence collection and covert action operations including counterintelligence and double agent operations working with the Federal Bureau of Investigation and military intelligence.” Jonna Mendez is known as a master of disguise, having served as the CIA’s Chief of Disguise, as well as a specialist in clandestine photography. The pair sat down with me at the International Spy Museum last weekend, at which point I popped a question I was dying to know the answer to: which spy movie is the most accurate? The most authentic? The one that even real-life spies like?

The answer: Tinker Tailor Solider Spy. Based on the novel by former real-life spy John le Carré, Tinker Tailor stars Gary Oldman, Colin Firth, Tom Hardy, John Hurt, Toby Jones, Mark Strong, Benedict Cumberbatch, and Ciarán Hinds, and focuses on an attempt to flush out a mole working in British intelligence. It’s not your typical Hollywood spy movie – there are almost no action scenes, no sexy moments. Instead, it’s a quiet, chilly character study about tight-lipped individuals trying to get a read on one another.

Tinker Tailor Solider Spy Trailer

“I can’t stand to watch [spy movies] when they’re not correct,” Mendez told me. “So the movie I call out [for its accuracy] is Tinker Tailor Soldier Spy. I love those kinds of stories about spies – action movies…not so much.”

“I have to second what Jonna said [in enjoying] Tinker Tailor so much,” Earnest added. “I was involved in counter intelligence, and Tinker Tailor is very much a duel of wits. The bottom line of which is: you identify a traitor – someone who has betrayed your group. That happens in reality, and I have been very close to that. So the consequence of it, and the effect it has on people, are very real to me. So I particularly enjoy that kind of spy film.”

You can read more about my visit to the Spy Museum, and watch a video of my interview with Earnest and Mendez here.