Low-budget, BBC-funded street-level action/horror movie with a socially-conscientious message, though very litle preaching. I talk at more length over at Stolen Recognizer.
If you get a chance to see this movie, do it so fast.
If you don't get a chance to see it, reflect on what you're missing.
This is the kind of movie that speaks to why horror or science-fiction movies can be interesting as stories, at a human level, rather than as unsettlingly prurient, violent spectacle. This is movie as provocation, not as catharsis.
Also, the kids talk like in Bromwell High.