Tense chav horror that skates round its really quite potentially offensive subject matter by showing some top notch horror chops.

Kelly Reilly (who instantly gets the film an extra star; rrrarrr!!) does the switch from timid to avenging angel really well, but Michael Fassbender is a bit underused, although definitely abused, the poor man.

The lead scrote is a malevolent force of nature, one of the nastiest screen creations you will ever see, and thankfully the near-unbelievability of his extremity is tempered by the dawning realisation of his cohorts that they've gotten themselves in way too deep.

I know some people hate this because of its almost phobic depiction of the working class, but taken on its merits as a genre flick, it's pretty damn good.