Best film of last year, and probably the best DVD of this year. Someone has set up a Shane Meadows website (I can't remember the web address, just type 'Shane Meadows' into Google), and he posts on there himself, and he has talked about the film and everything.
Anyway, everyone should see it. I didn't predict the twist the first time I saw it, but it's one of those where you spot something new every time you watch it, which explains that bit further.