A splendid all-British cast, headed by Malcolm McDowell, carries this well-crafted character-driven portrait of London's Sixties gangland - the first full-length feature from Paul McGuigan (The Acid House) - to a T. Casting is the key to success. There isn't a single face on the screen, no matter how secondary, that isn't made to count.

Given the benchmark set for the British gangster genre by Lock, Stock and Two Smoking Barrels it's hard not to shake off comparisons in some respects - particularly the last, somewhat disappointing minute - but really this film is a very different beast, much darker in its vision, far less glib in its portrayal of violence.

The simple story charts the unsettling obsession of the apprentice "Young Gangster" (Paul Bettany) for his mentor Freddie Mays (David Thewlis), the Butcher of Mayfair, a man "arseholed on the smell of success". Through emotions too hard for him to fathom, the sinister apprentice is led to contrive a coup that involves betrayal clinched by a truly savage act of ironic, perverted loyalty. The result: a monster is unleashed.

The past, however, catches up with him in present day London. With the release of Mays from prison, time served and reformed, Gangster (three decades on played by McDowell) is driven to confront almost unfathomable existential demons. When Mays looks all set to become the family man, it is the catalyst that unbalances "Young Gangster".

Karen (Saffron Burrows) is the night club singer with whom Mays gets engaged. Her time on screen is short, but pivotal. The performances in a stand-off scene between Bettany and Burrows, are gripping and expose a depth of malevolence in Gangster which gives a genuinely tragic depth to the action that will follow.

But it's not just the closeness and intensity of its character portrayal, but the way the Sixties is captured without the least scrap of glamour or sentiment that is distinctive. This is a film that more truly breaks the bounds of its genre than some of its recent acclaimed predecessors. The existential conotations opened up here show that the British take on the gangland theme really does have genuine mileage for power, depth and intensity.