In a lot of ways, this is a puzzling movie. Every single element of it is so right, so how does it end up being so completely uninvolving that I ended up nearly falling asleep halfway through? The problem isn't the casting; Colin Farrell makes a hell of a gangster, all smouldering machismo stomping through the streets of London. And with a supporting cast that includes Eddie Marsan (sleazy), David Thewlis (sleazier) and Ben Chaplin (sleaziest, and very, very good), Farrell has some excellent support. Ray Winstone has never been scarier, but of all people it's Anna Friel who takes the acting honours as Farrell's sister, a woman who out-sleazes Marsan, Thewlis and Chaplin combined.

The problem isn't the locations, or how true to life they are. I lived in London for a long time, and I've rarely seen the city depicted better, all back streets and alleyways with nasty bastards lurking around every grubby corner. Considering the film's writer and director William Monahan is from Boston, I was worried that this might be the tourist's eye view of London, but that really isn't the case. The film positively drips with atmosphere, and the expletive-heavy dialogue rings true.

And yet it all sits there, lifeless on the screen, a collection of images and characters that seem only vaguely related to one another. It doesn't help that the main plot - will Farrell become a proper gangster, or will he end up with Keira Knightley's way-too-good-for-him actress - is hardly new. But that doesn't have to be a deal breaker, and there are plenty of interesting minor characters to pass the time.

The problem is really that the film feels rushed. Those minor characters aren't given nearly enough time - Marsan gets three scenes, none of them remotely important to the plot, and even Anna Friel doesn't get a lot to do. She's still better off than Stephen Graham and Sanjeev Bhaskar, great actors who are cast in completely pointless roles that could have been played by anyone. And so much of this movie feels tacked on, from the dozen or so subplots, to Winstone's pointless murder of the wrong man halfway through, to the stalker, obviously based on Mark David Chapman, who makes several ominous appearances and is then dismissed in a single line of dialogue.

If some subplots and characters are pointless, though, the ending made me feel that way about the whole damn film. Without giving too much away, it's a horrible, limp lettuce of an ending, with none of the resonance that the film-makers clearly thought it had achieved. That's the film in a nutshell - it wanted to be profound, but ended up as a giant 'so what?'