The Courier

"Is it possible you work in a different branch of her majesty's government?" When Benedict Cumberbatch as 1960s businessman as Greville Wynne delivers this loaded line to a taciturn dignitary, it's a revelatory glimpse at an overlooked figure in the history of how close we came to nuclear apocalypse, it's a perfect moment for the character and the actor.

In true-life spy drama The Courier, Wynne is always an unlikely figure to help save the world. He's what you would call a good chap: solid, a little doughy (as noted by a running gag about his inability to pull off a push-up), good at wining and dining business contacts in Eastern Europe, but not the kind of man you'd send to save the world. He's even a little starstruck when he has lunch with actual spies – a title he would never bestow upon himself, even when he became the key intermediary between Western Intelligence and Russian intelligence officer Oleg Penkovsky (Ninidze). Starting in 1961, Wynne, a British businessman, carried secrets from Penkovsky to the West, many of them about Russian nuclear deployment, including deployment of warheads in the Cuban missile crisis. Both men risked everything, and ended up paying terrible prices, and The Courier is almost much about Penkovsky as it is about Wynne. After all, the film was originally titled Ironbark, the CIA's name for the dossier of information that Penkovsky provided to them.

The Courier isn't about high espionage thriller antics. It's not even really about the kind of agents who would be one of Smiley's people. These are the people that Smiley's people would use for dead drops. It's the quiet, raw fear of the amateur, not carrying secrets because it's the cool thing to do, but because of the overwhelming terror that not doing so will lead to nuclear doom.

It's in the final footage – an archival interview with the real Wynne – that the perfection of Cumberbatch's performance is expressed. Gaunt, reserved, unexpectedly thrust into the spotlight having risked life and limb to avert nuclear war, he's a figure from a bygone time, a bygone culture, and that's what Dominic Cooke captures so perfectly. Just as his last feature, On Chesil Beach (also set, coincidentally, in 1962), tackled postwar, pre-sexual-revolution gender roles in British middle class society, so The Courier is about the birth of nuclear angst. In one quietly devastating scene, CIA officer Emily Donovan (Brosnahan) breaks the myth of the four-minute-warning down for Wynne, and his inward collapse is born of an era of understatement and restraint. In that, Cumberbatch is matched by Buckley as Wynne's wife, Sheila, who must embrace just as much stiff-upper-lipness as her husband when the espionage is uncovered. The Courier never sells that as a virtue or a failing, but simply what is.

That's where it's easy to miss the quiet power of The Courier. The past is a foreign country, to be sure, but to let those people who lived, breathed, suffered, and sacrificed there live again is to open its borders, even if briefly.