"Blitz" opens on Jason Statham's character Tom Brant interrupting three young men trying to steal a car and, when they threaten him and demand his wallet, he beats the crap out of them with a hurley. We find out shortly after that that he's a police officer, and this is his general attitude. It's soon established there's a serial cop killer on the loose, and he's targeting police in South East London, Brant's branch. Brant uses his unsubtle techniques to get the information he needs - and somewhat surprisingly works with the new transfer and head of the investigation, Porter Nash (Paddy Considine). Although maybe this isn't too surprising, as we learn early on that Nash, when pushed far enough, will also step outside the law.
Statham isn't a brilliant actor. He's very good at the physical roles, and can be quite charming - and that's what's kept him employed for so long. Here, they put him in a character almost totally devoid of charm, leaving a violent and unpleasant man without a lot of depth - Considine and Aiden Gillen (as the killer) shine by comparison. The writer did manage what I thought was a surprisingly satisfying ending (although totally illegal - no surprise there). The end product is just "a cop movie with Jason Statham in it," no great work of art and definitely one to switch your brain off for, but if that's your thing it's serviceable entertainment.