The director of the documentaries Project Nim and the sublime, thrilling Oscar-winner Man on Wire, helms a compelling arthouse thriller about betrayal and redemption in Troubles-era Belfast.
Screenwriter Tom Bradby, who adapted his own novel, was a TV journalist in Northern Ireland in the 1990s and his spare script, which trusts the actors to manage with scant dialogue, has a scent of dangerous authenticity about it.
Riseborough plays solo mum Colette McVeigh, whose Republican staunchness is explained by a vividly drawn opening scene set in the 70s. Flash forward 20 years to 1993 and, in an astonishing wordless sequence, she's caught red-handed after leaving a suitcase on the Tube. Within 10 minutes of the opening titles she's detained and interrogated by an MI5 agent (Owen) known only as Mac and he's enforcing a deal that anyone following Homeland will recognise: you work for us, Mac says, and "nobody dies; nobody gets hurt".
You brace yourself for an intertitle saying "Yeah, right" but the rest of the film is as murky and uncertain as the opening was straightforward and lucid.
We're dragged into the tiny West Belfast council house Colette shares with her mother and her IRA brothers, the fanatical capo Gerry (Gillen) and the war-weary Connor (Gleeson). But we have no idea whether she's going to stick to her deal with Mac; in fact, we have no idea whether she has any idea.
