Rumours that Chris Morris was making a film about Muslim terrorism sent shivers of fear through the spine. Would this cinema outing result in The Day Today and Nathan Barley being thrown into the recycling?

The bombastic comedian derives humour from taking real phenomena and propelling them to their excruciatingly painful conclusions. Subtlety was not previously in his vocabulary.

His treatment of paedophilia was brilliant and attacked the right people – but always threatened to veer into the unacceptable. That was a great part of the pleasure.

With Islamophobia dominating the headlines and once leftwing journalists like Nick Cohen and Christopher Hitchens drunkenly lurching to racist conclusions, one feared an explosive diatribe informed by the inanities of the chattering classes.

Instead, Four Lions is a huge departure for Morris. The humour of the film is defined by a single concept – that the perpetrators of the London bombings were not all that sinister, not all that different and not all that capable. It is overall gentle, human, understated.

Many of the jokes are simple slapstick.The violence is too comic to equate with terrorism. The characters are two dimensional in their stupidity. But the portrayal of the terrorists is strikingly sympathetic: they are not demonised.

Omar (Riz Ahmed), the group “mastermind”, is motivated through personal grief, through politics and a desire to be taken seriously. The viewer is asked to empathise with his decisions and understand his predicament.

A scene where he uses a story he is telling his son to think through his mistakes and decide whether to deceive his “cell” is genuinely poignant.

The film’s comic turn results in fascinating political conclusions. Why is the entire country being driven to the right, accepting greater government authoritarianism and inhuman and unlawful actions by the police, the secret services and the army?

There are very different portrayals of Muslims in this film – all of which are the victims of Morris’ perverse humour. Notably, the assumption by the police that the most devout Muslim must be the prime suspect is shown to be wholly wrong – with tragic consequences.

Their foolhardy and childlike attempts to commit acts of terrorism – blowing up crows, microwaves, sheep – are simply comic. The unstated comparison would be with the IRA who successfully blew up large parts of London and the Conservative Party conference in Brighton.

The real villains of the peace are the police and secret services. Shock, laughter and ultimately anger follow the fact that the shooting of a bear during the London marathon, the raiding of the wrong house and extraordinary rendition are all closely based on reality.

For many on the Left this film should never have been made. The Muslims depicted are by design terrorists or fundamentalists. Islamophobia is no laughing matter and any stereotyping feeds the mainstream demonisation and racism.

Infantilising the enemy is a familiar imperialist trope. The fact Muslim terrorists are shown as otherwise ordinary blokes could lend itself to the pervasive racist assumption that ordinary Muslims could be terrorists. This is the journey I feared Morris would follow.

However, the really sick, dark, nasty, spiteful joke is that so many people in Britain have quietly acquiesced to a narrative about Muslim extremism which has led to our civil liberties being stripped away, to innocent people being killed and tortured, to asymmetrical war.

We have done this when the “terrorists” are themselves laughable. Amateur. Na√Øve. So prone to Morris’s ridicule that we have to ask: in who’s interests were they used to frame political debate in this country for the last decade?