This British thriller by James Marsh (Man on Wire) is a little too neatly scripted and tightly edited for my taste, but there are galvanizing performances from Andrea Riseborough, as a Belfast mother who’s mixed up in the Provisional IRA, and Clive Owen, as an MI5 agent who turns her against her comrades. A prefatory scene, set in 1973, shows the main character lazily sending her younger brother on an errand and then watching him die on the kitchen table from a bullet caught during a street battle; two decades later, she’s helping set up a terror attack on the subway when she’s picked up and threatened with the loss of her son. Tom Bradby adapted the screenplay from his own novel, though the basic story stretches all the way back to Liam O’Flaherty’s 1925 novel The Informer. With Gillian Anderson and Domhnall Gleeson.