Drone warfare is a hot topic these days and a prime target for some compelling cinema. And so, in swoops Eye in the Sky, a timely film that wraps difficult moral questions in the guise of a taut, against-the-clock thriller.

A particularly super Helen Mirren leads the film as Katherine Powell, a British military colonel who is in command of a sensitive and dangerous operation to capture suspected terrorists in Kenya.

She decides to switch the objective of the mission from “capture” to “kill” when surveillance shows that a safe house contains suspected extremists strapping bombs to their chest. But the mission suddenly escalates when an innocent young girl enters the kill zone, causing the powers that be to question if the operation should continue.

The majority of the film is basically one big, expertly devised set-piece – bookended by a tense build-up and a thought-provoking denouement – in which we flit between various different viewpoints.

There’s the drone’s-eye view of the targeted zone, the soldiers in control of the drone (played by Aaron Paul and Phoebe Fox) caught between the proverbial rock and a hard place, the government advisers (one of whom is played by the late, great Alan Rickman, to whom the film is dedicated) and Mirren’s increasingly exasperated colonel. And it’s a testament to director Gavin Hood (Ender’s Game, the Oscar-winning Tsotsi) that he is able to keep things gripping and wholly unpredictable for the entire segment and beyond.

The moral questions and dilemmas are plentiful. What does conscience mean in modern, technologically armed warfare? Where does legality factor in when fighting terrorism? Is one life worth sacrificing to save the many? Eye in the Sky asks these sorts of probing, difficult questions in forceful fashion without leading us to easy answers or any sort of trite, spoon-fed conclusion.

It’s not the first war film to come at it from the drone perspective – last year’s Good Kill flew in the same ethically dubious skies – and it surely won’t be the last. But as it stands it’s a tightly wound, complex thriller that plays as much on our moral compass as it does on our jangling nerves.