The idea for Channel 4’s one-off film Complicit began back in 2009, producer Kevin Toolis explains, strangely enough with something that Gordon Brown said.

In a statement, the then Prime Minister said that “the British state doesn’t do torture”. Toolis thought it was such a strange and obvious thing for the PM to point out, and that – given allegations against the nation at the time – it was something worth exploring in drama. Thus, Complicit was born.

Starring Spooks alumni David Oyelowo as Edward, an MI5 officer who is convinced that another 7/7 style terror attack is imminent in the UK, embarks on a witch-hunt against British national Waleed (Asher Ali), believing him to be a terrorist. Having been wrong before his superiors are reluctant to trust him without any hard evidence (not to mention the subtext that a working-class, black man is at an inherent disadvantage in this environment), and his investigations are stalled by bureaucracy and red tape at every turn.

As Edward becomes increasingly desperate to prove his theory, he must tackle one of the most provocative and complex questions of our time: is it ever okay to allow the torture of another human being? Indeed, is it Edward’s duty to allow the torture another human being, if it will save British lives?

Directed by Neill MacCormick and written by Guy Hibbert, the premise will bear unavoidable comparisons to Channel 4’s hit US import Homeland, given the premise of a perceived to be unreliable protagonist trying to stop a terror attack that nobody else believes in, but also with Zero Dark Thirty, Kathryn Bigelow’s latest film which also tackles the taboo of torture. However, Complicit is a different kettle of fish to either one of them.

Shot and paced with deliberate sparseness, Hibbert’s script and MacCormick’s direction creates a very calm and stately piece of television. There are long stretches where Edward doesn’t speak and, frankly, nothing very much happens. This is in stark contrast to Oyelowo’s previous work – Complicit is the anti-Spooks.

This is important for the naturalistic tone of Complicit, but also helps the audience to get inside Edward’s head. Any frustration at the slow moving plot merely helps us feel Edward’s frustration at the lack of progress with his investigation. There’s definitely something to be said for such a measured pace, but some might find that Complicit takes it to an extreme.

While some may find it boring, the quiet, contemplative and stilted nature of many of the scenes only serves to heighten the impact of the pivotal sections where something does happen – namely the scenes where Edward and Waleed come face to face.

These scenes – particularly the pivotal, extended interrogation in the middle of the piece – are electric. Oyelowo and Arsher Ali are incredible, as their characters face off and discuss their opposing notions of Britishness, race, right and wrong, religion and their different ways of life, and try to provoke each other into a reaction. It’s a game of chess and it’s a boxing match, and it’s one of the most incredible scenes you’ll see this year.

While it would be incredible regardless of the rest of the piece, that the surrounding parts of the film are so still and quiet make this release of all that pressure – this explosion of dialogue – have far more impact than it might ordinarily. Asher shines in his scenes, while Oyelowo – on screen for nearly every minute of the film – carries the piece ably, expertly conveying what his character is thinking even in the many silent moments.

Complicit is an entirely deglamourised look into the anti-terror work MI5 does, and tackles complex moral quandaries without providing any clear-cut answers. Complicit doesn’t preach; what’s right or wrong is for the audience to decid. And while this is ostensibly about torture, Complicit is more thoughtful than exploitative.

Anyone expecting scenes of violence and torture like those recently seen in Channel 4’s Utopia are to be sorely disappointed. Complicit has other things on its mind, and manages to be far more shocking in depicting its two main characters just talking than any scene of graphic violence could hope to achieve. It may not be for everyone – really, the slow pace is too slow for the most part – but the thought provoking nature of Complicit is undeniable. And it really is worth tuning in for that central scene alone.

Airs at 9pm on Sunday 17 February 2013 on Channel 4.