Based on a true story, and on the facts - insofar as they will ever actually be known - this is a gritty and quite depressing depiction from Kathryn Bigelow of one traumatic night in the city. It was during a night of rioting that a squad of police officers respond to reports of gunshots at a city hotel. Upon entering they discover a group of black youths, a couple of white girls - and what follows is a potent mix of racial hatred, bigotry and violence as the boys in blue leave what integrity they might have had at the door and leave again with three dead bodies and nine others savagely beaten to show for their policing efforts. Will Poulter sheds his nice but dim "Harry Potter" image and is really effective as the lead officer bent off exacting his own stye of justice, Ben O'Flynn also works well as his complicit sidekick and there are strong performances from Anthony Mackie, Algee Smith and from John Boyega as the state policeman trying to do his best to tread the very perilous line between law enforcer and African American. It shies not from presenting us with a ghastly human face for the spontaneous and plausible attitudes of superiority and disdain held by the polices and depicts with some menace how their captives are terrified and humiliated by the people they ought to heave been able to trust - and that extends to the "slutty" two white girls too. It's really one ensemble effort, the direction is taut and at time the whole thing just has a relentlessness that does make you wonder (I am not an American) how the hell this could ever have happened in a land that purported to be civilised and free (in 1967). Not an easy watch, but the events in Detroit 50-odd years ago still resonate with issues of policing and racism just a potently now, as when this is set.