The image of the bomb is an apt one for Shadow Dancer. As a hunk of parts with a timer, there’s nothing naturally threatening about a bomb; it’s the explosion that matters. Hitchcock was right, and in this IRA thriller from James Marsh, incendiary devices are all over the place. Some are literal, most are figurative, and Bomb Theory abounds. It opens with the shocking death of a young boy, surrounded by his family as blood pours from a bullet hole in his chest. It’s a direct insight into the fight the members of the IRA hold as sacrosanct and the guilt that the boy’s sister feels over sending him out into the streets on a simple errand. That sister, all grown up, is Collete McVeigh (achingly performed by Andrea Riseborough). After dropping off a suspicious bag in a tube station, she’s picked up by the authorities and taken to see Mac (Clive Owen) who dangles the promise of hard jail time in front of her until she turns reluctant informant for the MI5. The people she’s betraying forced her into a war, but they’re also her family.