Humour is interesting. Being funny is often about accepting shocks that are delivered in a way that makes it clear that you the audience are still safe, despite things appearing otherwise for the characters that the joke concerns — whether literal ones depicted by actors, or ones conjured by the imagination of a comedian. No surprise then, that perceptions of what is funny vary — one person’s safe territory is another’s danger zone.

Witness the recent minor furore over Frankie Boyle finding humour in Down’s Syndrome. To me, the taste failure lay in him picking on a pretty much voiceless group, it being pretty much a given that people with learning disabilities are less capable than most of speaking up for themselves. Others might find the notion of humour about disability at all to be taboo, their own delicate sensibilities being of more concern than any empathy with Down’s sufferers.

Enter Chris Morris. Famed for his ability to sniff out media cant and hypocrisy and reflect it back in the form of some truly twisted humour that itself has become the subject of media attention, his latest project is the film Four Lions. Terrorism and satire are two words you don’t often come across in the same sentence, triggerhappy dogmatists not being high on the list of people you’d want to get on the wrong side of. The bomb found recently in the proximity of South Park’s creators confirms that such fears are well founded.

Scripted by Morris along with writers Sam Bain and Jesse Armstrong, the film is thankfully much more on a par with the latters’ edgy work on Peep Show than their limp feature Magicians. It features a group of wannabe Muslim freedom fighters living in Yorkshire, all but one of Pakistani origin but perhaps the most intense being a white guy, a loser who puts the zeal into zealot.

What makes it work so well is that the Al Qaeda apprentices are depicted as a regular group of friends, who in other circumstances might share a love for football or poker but in this case have a thing for jihad. And why not? Their case that capitalism is morally bankrupt might be exaggerated, but how much? Increasingly, even conservative thinkers are disgusted at the antics of bankers — so why not blow the whole system up?

Well, because mass slaughter is a surefire way to kill lots of people who have very little to do with the mechanisms of capital, but are victims of it themselves. One of the scenes shows the terrorists identifying their targets — this one a banker, that one a gynaecologist, but none of them innocent, an impossibility within the logic of the terrorists. Only, that logic comes increasingly unpicked as the story develops, and the friends come closer to putting their plans into practice.

It’s exemplified in the debate between the group’s leader, a bright and articulate man less fundamental in his views than his pacifist brother, and their resident dimwit. The latter functions as a barometer, his straightforward fear and lack of comprehension meaning he needs to be pretty much conned into going along with the terror plan — a job of confusion which turns from comic into something genuinely moving when the none-too-bright guy is caught up in a hostage situation at the climax of the film.

Some reviews have suggested Chris Morris has held back from the force of the attacks he’s unleashed at other targets, but that entirely misses the point. This is a film that humanises people who are demonised even more than the IRA were in their day — their culture, dress, and skin colour marks them out as other in a way that goes way beyond anything to do with their beliefs, which at the end of the day aren’t any more bizarre than many people with strong religious or political views.