Down on her luck Pole, Lena (Olga Fedori), has started work at the airport. Clearly unhappy with her lot and praying that her bog cleaning duties are but a brief pit stop, she politely rebuffs Birdie (Ainsley Howard) and her mute brother Elbie's (Toby Alexander) invite for a post work drink. But when Lena misses her bus home, the amiable but pilfering Birdie offers her a lift courtesy of 'Dad' (Perry Benson) if only she'll follow her home, a short walk from the airport. Reluctantly, Lena agrees and things quickly become very nasty indeed as she's subjected to an inversion of Hostel's Eastern Europe attack on the West.

Initially it's entirely straight and gruelling horror, but soon the sheer surreal absurdity of the situation elicits some hysterical (though incredibly dark) exchanges. This really is the blackest of black comedies. In a wonderful subversion of kitchen sink dramas and soaps, Mum and Dad emerge as the ultimate purveyors of working class family values, but with repulsively warped psycho-sexual tendencies. Sheil cleverly plays on the stock characters (and caricatures) found in so many of the mundane EastEnders-style soaps on British TV, lifting dialogue almost wholesale from these staples, and then taking their disciplinary ideals to gruesome extremes. If you don't behave yourself, Dad will do an awful lot more than just ground you.

A wonderfully sickening meal time sees Elbie carrying plastic bags of assorted body parts across the kitchen to dispose of them when the bags split. As blood oozes out, it's treated as an everyday occurrence, a domestic chore; Elbie is casually chastised and the whole family have a good laugh. Shut your eyes and it could be a scene from EastEnders. There's plenty of humour elsewhere too. Even in the bleak opening minutes Lena attempts to befriend Elbie with small talk on how his sandwich looks nice – it's the most insipid petrol station-supplied blandness you could imagine.

Perry Benson is superb as Dad, perfectly mixing comically banal fatherly chat with outbreaks of extreme violence. Dido Miles's Mum too is a suitably doting counterpart, making the dynamic between the couple entertaining and strangely believable, warning the kids not to enrage Dad in a sly display of mock empathy.

There are some problems with Mum & Dad. We never really route for Lena as person, only as the notional heroine. Her back story is of the briefest order, and that's partly the point - she's simply one in a string of transient immigrant workers, lost in the shadow of Heathrow's jets. But this does make the denouement rather hollow, and more than a little underwhelming. The Heathrow setting and multitude of minimum wage workers who spend their days watching people jet off on holiday is fertile ground for the sort of social and cultural commentary that the horror genre can lend itself so well to. That more isn't made of the situation seems a wasted opportunity. We spend almost the entire film inside the 'family' home creating a suitably claustrophobic atmosphere, planes overhead rubbing salt in the wound of someone who's trapped within walking distance of not just escape from Mum and Dad, but from the whole country. This narrowing of scope would be fine if there was more meat on the bones of the story, but as it is you can't help but feel slightly cheated at the wafer thin premise.

The film strives to shock with moments that will induce nervous laughter, but its excesses quickly become amusing and so any scares dry up. Treat it as the twisted black comedy it so often is, however, and there's much to enjoy, allowing you to forgive its decidedly 'one trick pony' execution.