In James Watkins’ 2008 thriller Eden Lake, a middle-class couple (Michael Fassbender and Kelly Reilly) decide to spend their weekend camping at the titular isolated lake. Their holiday is interrupted by a young gang of youths. Arguments between the two parties escalate, until the couple are trapped in a desperate scramble to escape the now-murderous children.

Horror, which Eden Lake certainly represents by its conclusion, is a very personal genre. Like comedy, where people’s senses of humour will differ from one another, the effectiveness of horror is going to depend on what the individual finds to be scary or satisfying. In the case of horror that is particularly true for violent forms of extreme cinema, sometimes mislabelled ‘torture porn’, where graphic scenes of blood and gore can easily turn off much of the audience. It is even more so for particular sub-genres including the New French Extremity, which add a queasy level of transgressive sexuality into the mixture. I have a high tolerance and indeed a strong personal interest in extreme cinema. The violence is not why I find Eden Lake so deeply offensive.

The film’s problems also do not stem from its use of violent children as the source of its horror. There is a long history and rich tradition of making children the focus of a horror film, whether via the homicidal crowds in Narciso Ibáñez Serrador’s Who Can Kill a Child (1976), the undead toddler of Mary Lambert’s Pet Sematary (1989), or the mysterious behaviour in Tom Shankland’s The Children (2008). It’s not even offensive because it contains images of extreme violence against a child, although I wouldn’t blame anybody who hated this film because it contains 12 year-olds getting stamped on the face until dead, doused in petrol and burned alive, or stabbed in the throat with broken glass.

Instead I find myself offended because this is a film that openly and unashamedly wallows in a privileged middle-class paranoia about the working class. It tells its audience not to trust seemingly filthy, untrustworthy poor people, who clearly don’t control their kids, are uniformly violent, drunk and abusive, and who would sooner murder an injured woman than call her an ambulance. It is a film, made in class-conscious Great Britain, that does not challenge or interrogate class divisions but crassly indulges in them instead.

I do not think it is a deliberately offensive movie. Instead I think its writer/director, James Watkins, has simply gone out of his way to provoke. He has picked up on some of the worst class-warfare attitudes of the United Kingdom and exploited them for cheap thrills. For some viewers, like me, it will offend. For others, it will be seen as harmless – if extremely tawdry – entertainment. For yet more it will be a de-facto confirmation of their worst prejudices: those people who sneer at those of a lower economic background, who’ve never had to struggle to pay their rent and bills, people who harp on about how much they hate ‘pikies’ and ‘chavs’ and otherwise demonise and degrade society’s most vulnerable.

‘I think,’ said Watkins in one interview, of his film’s torture scenes, ‘it’s very far removed from the sort of gleeful celebration of violence you get in a film like Saw.’ He is indeed correct that Eden Lake is not like Saw. Saw was deliberate grand guignol, and an overtly satirical indictment of contemporary American apathy. Eden Lake is about thuggish young poor people in hoodies flicking an open box cutter around in Michael Fassbender’s mouth.

Technically it is a very well-made film. It is excellently photographed, and the actors do all give their all in expressing the rising tension and panicky desperation of the piece. Sadly it is all in service on something unpleasantly wrong, a disagreeable narrative that sticks uncomfortably in the throat and makes the overall experience a horrifying one for all of the wrong reasons.

This is grossly irresponsible, deeply unlikeable filmmaking. It is insincere, and wastes a great deal of talent making something genuinely unpleasant. Some films you are going to like, and some films you are going to dislike. It is a rare feat for a filmmaker to direct something you literally despise.