Equally indebted to Martin Scorsese, Guy Ritchie, and Giorgio Armani, London Boulevard represents the apotheosis of style over substance, the kind of gangster flick where the cut of a killer's suit is as important as the motive for his crime. That style is so strenuously presented, whipped into a creamy foam of guns, Rolling Stones tracks, and expensive cars, that it manages to get by mostly on vapors, anchored by the film's pitch-black presentation of London's mob underworld.
Freed from prison after serving a few years for manslaughter, Mitchell (Colin Farrell) is determined to go straight, the kind of doomed aspiration that indicates he'll be back in the game by the 45-minute mark. His reentry to a life of crime comes via Billy (Ben Chaplin), a goofy old friend who works as a low-level debt collector, eventually connecting Mitchell with ruthless boss Rob Gant (Ray Winstone), who cements that connection by making him an accessory to a violent crime. Most of the film concerns Mitchell's attempts to break his orbit with these two unsavory characters, pulled toward the light by reclusive actress Charlotte (Keira Knightley) after he begins working as her personal security.
All of this plays out with well-paced efficiency, so that it's not entirely a problem that the film acknowledges its influences while never attempting to escape them. But a movie like this lives and dies by its finer details, and London Boulevard screws up by applying the same broad brush to its entire cast, meaning every character gets the same amount of shading. This results in greater color for incidental players, like the unnamed mob heavy played by Stephen Graham, never shown without a fruity, ridiculously elaborate drink in hand. At the same time, bigger characters like Gant, whose penchant for expressive violence makes him Mitchell's main adversary, is developed just as sketchily: He's a brutal homosexual with a taste for combining business with pleasure, a trait that comes off as more roughly offensive than pulpy.
This tendency to cut corners leaves London Boulevard feeling increasingly shaky as it progresses, leaving us with characters whose motivations are never really explained beyond the roles assigned to them (mobsters, when left to their own devices, will try to kill each other, etc.). It's also probably not the best idea to have Knightley's character pontificate about the futility of female characters in action movies, how they're only around to reflect back how interesting the male hero is, when she's doing exactly that herself.
But where the film loses strength in its muddled characterizations, it gains potency from how gleefully dark it becomes. Despite sharing Ritchie's fascination with '70s revisionism and rough men calling each other cunts, London Boulevard inevitably has more in common with the Mike Hodges school of steely English gangsters, positioning Farrell as a modern-day acolyte to Michael Caine's genteel bruisers: well-mannered and polite, but ready to smack a woman or two around if it comes down to it. It doesn't hurt that Monahan has assembled a top-tier cast, with small turns from actors like Eddie Marsan and David Thewlis, presenting a world that, while lazily familiar, at least feels somewhat lived in.