Detroit The finest acting you’ll see all year

Kathryn Bigelow’s Detroit is about the events in an American city one night 50 years ago, but its outlook stretches a lot farther than that. In her third collaboration with screenwriter Mark Boal, after The Hurt

Locker and Zero Dark Thirty, Bigelow has made a film about her country’s deep-seated derangement on matters of race. As recent events in Charlottesville, Virginia, suggest, the last chapter of this story won’t be written for some while yet.

In late July of 1967, at the height of a five-day riot sparked by a violent law-enforcement crackdown on an unlicensed African-american drinking den, three black teenagers died from gunshot wounds sustained over a mile away at the city’s Algiers Motel, during a raid on the property by police and the National Guard. Detroit pegs out the context of their deaths with nerve – and the opening and closing chapters of Bigelow’s film have just the sparky jumble of perspectives you’d expect, with the camera weaving through the unrest as if it’s trying to triangulate the truth at close quarters.

Yet the central motel incident itself becomes a bottleneck the entire film has to squeeze through – and squeeze it emphatically does, and you along with it, until you swear you can hear your own skeleton splinter and creak. As a handful of mostly black guests are rounded up and tormented by three white officers under the pretence of a search for a (non-existent) sniper, the period detail melts away to be replaced by a sort of mad lucidity, as if you’re somehow watching this lunacy live.

Bigelow is more than ably assisted in this by her exceptional, and mostly quite young, ensemble cast. Every individual caught up in the wider story has one of their own, from Anthony Mackie’s recently returned Vietnam veteran Greene, to Algee Smith’s Larry, a singer who finds himself singing for his life. Then there are the two young white women from out of town, played by Hannah Murray and Kaitlyn Dever, whose mere presence among black men in a good-time context, is like petrol on the flames to the police.

The three policemen, Krauss, Flynn and Demens, are played by Will Poulter, Ben O’toole and Jack Reynor, and range from a blithely bigoted dunce in Reynor’s case, to Poulter’s horrifically plausible psychopath. Brilliantly, the first words Boal gives Poulter’s character aren’t bloodthirsty snarls, but an apparently level-headed monologue on how the city is failing its black residents, delivered during a routine patrol. This makes Krauss’s subsequent conduct a thousand times more chilling: we know he is completely blind to the madness in his method.

It’s a mesmerically assured performance by the 24-year-old actor, shot through with toxic menace, and its spirit – call it the Poulter-geist – hangs over every last scene of the film,

Once the significant shock of the film fades, what stays with you are its implications

ramping up the tinderbox tension to ever more unbearable levels. An equally crucial factor in the film’s baleful chemistry is Melvin Dismukes, a private security guard played by Star Wars’s John Boyega, who becomes an uneasy half-witness, half-accomplice in much of what unfolds.

Neither side can be certain Dismukes is one of their own. He’s nominally on the same team as the lawmakers, and, because he’s black, he’s easy to brand a collaborator and an “Uncle Tom”.

There are two points in Dismukes’s story at which Boyega delivers, in a split second, some of the best screen acting I’ve seen all year: the first in a police interrogation following the incident, and the second at the conclusion of the trial. Both involve his character reshuffling everything he thought he knew about the rule of law.

Once the significant shock of the film fades, what stays with you are its implications – the way it shows division digging in, with each flare-up making the next more grimly probable. This is history retold in the blistering present tense.