John Michael McDonagh (brother of Martin-In Bruges-McDonagh) brings his Sundance smash to Edinburgh as the festival opener, to similar success. Sharing his brother’s taste not just for spicy language and biting sarcasm, but also pulpy subject matter with corrupted protagonists rediscovering a sense of purpose, his debut tells the story of disillusioned Irish police Seargent Gerry O’Boyle (Brendan Gleeson), who odd-couples it with FBI Agent Wendell Everett (Don Cheadle) to bring down a  huge drug deal in Galway.

A simple story that allows us to focus on the rather roguishly endearing central character, O’Boyle is a sergeant who pops acid when he finds it on his victims, hires prostitutes on his days off and speaks in appalling racial generalisations (“I thought all drug dealers were black – or Mexican”), yet he remains sympathetic throughout, mainly because of the flippant charm McDonagh and Gleeson invest him with. Cheadle’s fish-out-of-water engages despite being a decided second fiddle, and the film occasionally has the warm glow of an old-fashioned buddy film, undercut with pithy political tensions (“If I die,” O’Boyle requests of Wendell sarcastically, “I want one of those flags in my coffin like you do with the boys in Iraq”).

But this is ultimately O’Boyle’s story. As he struggles to garner back from life the purpose years of meaningless work in a barren town has taken, McDonagh captures excellently the resilience of an Irish culture still recovering from imperial rule; “There were gay people in the IRA?”, O’Boyle asks as he hands over a bag of guns, “One or two”, comes the response, “it’s the only way we could infiltrate MI5”. This is also manifest in the way O’Boyle is stubbornly resistant to all forms of cultural imperialism; when a film-buff policeman assures O’Boyle that “I’m on it, Searge”, O’Boyle is disgusted; “He thinks he’s in fucking Detroit”. Whether McDonagh’s use of Rawhide-like Westen geetar music is therefore hypocritical or intended irony is unclear, but you’ll no doubt be far too pleased to care.