The film opens with an unnamed, middle-aged British gangster (McDowell) attending a boxing match. Upon hearing the name of Freddie Mays in the conversation, he becomes upset and leaves without a word. He then enters a toilet and sets his glass of champagne on the floor near the urinal. As he urinates, some of his urine splashes into the glass. He picks it up and stops just as he's about to drink from it, looks to the camera and says, "What do you take me for, a cunt?" The film then flashes back to the 1960s, with a younger Gangster (Bettany). He comes to the attention of a very influential London gangster, Freddie Mays (Thewlis), who recruits him to be an enforcer for his gang. The Gangster is eager to please, and proves his loyalty to Mays by enthusiastically dropping a car onto a mechanic's head after he attempts to stab Mays. The Gangster quickly becomes obsessed with Mays' glamorous lifestyle and success, ogling his expensive suits, his watch, and in particular his tie-pin. The Gangster's obsession becomes more intense, to the point of wanting to be Mays, even picturing himself sitting in Mays' place. The Gangster soon discovers that Mays' main rival, Lenny Taylor (Jamie Foreman), is planning on killing Mays. Instead of warning his boss, the Gangster decides to let the attack take place, even killing a member of his own gang who was set on going straight to Mays. The attack goes on as planned, and the Gangster sits in a car nearby to watch as the assassins gun Mays down and cut his fiance Karen's neck. That same night, the Gangster shoots Lenny in the leg, and then calmly turns up the Hi-Fi to drown the resulting screams. The Gangster tortures Lenny with a wine bottle, an axe, an ice pick, a machete and a fruit bowl, all amid a constant stream of kicks and verbal abuse. He finally kills Taylor by ramming his head through a pane of glass, then smokes a cigarette while continuing to curse at his victim's corpse. Most of the scene is shown from Taylor's point-of-view, with images and sounds fading in and outas the victim moves in and out of consciousness and slowly dies. To the Gangster's surprise, Freddie Mays and Karen did not die in the attack. However, Mays is unjustly convicted of Taylor's murder and sent to prison for 25 years. With Mays locked up and out of the way, the Gangster consolidates his power over the city's underworld. In the intervening years, he organizes a bank heist, runs a casino, fixes horse races, and builds his gang to 300 men strong. At this point, the film returns to 1999, with the Gangster once again portrayed by McDowell. Mays finally comes out of prison a changed man, holding a bachelor of arts degree. The Gangster is ready for a battle, but Mays seemingly has no fight left in him, wanting only to marry Karen and retire in peace. He tells the Gangster that he is welcome to the London underworld and will not stand in his way. The Gangster is furious that Mays is seemingly happier with nothing than the Gangster is with everything, and threatens Mays with a gun. He then gives Mays the gun and begs him to kill him, but Mays merely smirks and leaves saying "Who'd wanna be Freddie Mays?". In the face of his rival's sneering indifference, the Gangster loses his mind and ends the film standing on top of a tall block of flats in his underwear, throwing money in the air and laughing maniacally. He finally leaps off the building to his death, declaring "I'm number one".