Here is a film about the war on terror that remains absolutely gripping throughout despite there being only a minimal amount of action. Showing the machinations and deliberations of those waging wars thousands of miles away from the action, it is reminiscent of the classic Fail Safe, and more recently last year’s War Book.

Helen Mirren stars as the hawkish Colonel Katherine Powell running a mission to track, capture and bring to trial two British and one American citizen who have become part of a terrorist cell in Kenya. Using on-the-ground local agents and sophisticated drones they are tracked to a house in an unexpected location that is too secure for an intervention. The option now is to let them go or to execute them using missiles fired from the drone. The problem with the latter choice is that it is almost certain to result in innocent casualties, including that of a little girl selling bread. When the surveillance reveals the terrorists are arming themselves with suicide vests, the need to intervene becomes urgent, but will they decide to accept the inevitable loss of innocent lives?

The tension gradually builds up in a way that I have not experienced since the Hurt Locker (2008). As the politicians hesitate and try to pass the buck in terms of who will ultimately make the decision, Powell and her colleague Lieutenant General Frank Benson (Alan Rickman) press them to go ahead with the missile strike. The arguments for and against that decision are all plausible, so whilst it is easy to become frustrated with the people involved, it is also easy to understand why the choice is so hard to make.

It is pretty hard to find fault with this taut story. Guy Hibbert screenplay is superb, realistic with some touches of humour and Gavin Hood’s direction is unfussy. You could argue that Mirren is too old for her part but she pulls it off and Rickman, in his last on-screen role, is excellent, with a telling final line. Of the rest of the ensemble cast, special mention should go Richard McCabe as the attorney general and John Heffernan as the legal counsel.

Terrific stuff all round and a certainty to be in my top five of the year.

Rating: 9.5 out of 10