Keep reminding yourself: it's only a movie.

Like horror movies familiar with that sort of tagline, terrorist comedy Four Lions' (read our review here) incendiary premise goes out of its way to suggest it really shouldn't be just a movie. The titular lions are a quartet of Muslim extremists; wannabe suicide bombers whose goal to disrupt the London marathon is no joke, but whose bungling and idiocy provides a comedy that'll keep you laughing until its (potentially) explosive finale.

It's no wonder that the media in the UK, where the film goes on general release today, is at turns amused and outraged. For some it's a well-observed and intelligent act of defiance out to ridicule the people it bases itself on. For others it's a deeply offensive joke at the expense of the victims of these acts of terror. But they're all in agreement on one thing: this is pure, grade-A cinematic controversy.

No wonder that it comes from Chris Morris, who's gone out of his way to redefine the word 'controversy' since he created spoof news show, The Day Today, for British TV in 1994. When his follow-up, Brass Eye, aired in '97, it blurred the line between the increasingly rife sensationalism of the TV documentaries it spoofed and comedy so surreal it's a wonder anyone took it seriously. Nevertheless, a 2001 special on pedophilia provoked more than 1000 complaints to the UK's Independent Television Commission.

Is Chris Morris the antichrist of British comedy, as so many opinion pieces in the UK would be keen to suggest this week?

There's no question that the film is drawn straight from the darkest headlines of the last decade. Nor that it isn't occasionally uncomfortable viewing. Scenes involving one of the terrorists at home leading a happy middle-class life with his wife and child, contrasted with the plotting he engages in with his co-conspirators, are particularly unsettling.

And for some families of the victims of the London terrorist bombings of July 2005, the comedy is a little too close to home. Graham Foulkes, whose son was amongst those killed in the bombings, told the BBC that he felt the film was very specifically based on the events of that day. He said it was about, "four lads from the north, all with strong Yorkshire accents - and the bombers were from Yorkshire ... That's not parodying or being satire about terrorists. It's making money about a specific attack."

But others have suggested the film may in fact strike a blow against terrorism by portraying its characters as the incompetent, irreligious narcissists they often are. Jamie Bartlett, author of The Edge of Violence, told the BBC, "It is important that [terrorists] are seen as such - as it can play a role in denting the brand of al-Qaeda."

Those involved with the film have stressed that it isn't intended to cause any offense or trivialize the events of 7/7/2005. But, as Morris is wont to do, it does provoke very valid questions about the role of satire in tackling subjects of great sensitivity.

It may only be a movie, but for many people the effects of terrorism have been all too real.