Given how a substantial portion of the British film industry has subsisted on London set gangster flicks over the past couple of decades (you can blame Guy Ritchie for the trend), it’s remarkable that the city’s most famous real-life mobsters, the Kray twins, haven’t found their exploits mined by countless low budget filmmakers. It’s 25 years since Peter Medak’s take on the subject, 1990’s The Krays, which cast pop-star brothers Gary and Martin Kemp as the title duo. Brian Helgeland’s Legend takes the next logical casting step, dropping Tom Hardy into both roles.

Unlike Medak’s film, which focused on the relationship between the brothers and their domineering mother, Helgeland’s film begins in 1966, with paranoid schizophrenic Ronnie newly released from a psychiatric ward, thanks to the intimidation of his psychiatrist. Waiting on the outside is his twin brother Reggie, who has been building quite the criminal empire in his twin’s absence. Thus begins a riff on Steinbeck’s Of Mice and Men, as Ronnie’s psychotic behaviour threatens to tear apart everything Reggie has built.

Every piece of marketing around Legend has centered around the dual casting of Hardy, and while it’s fascinating to watch at the outset, it quickly becomes a millstone around the film’s neck. The effect is quite poor when compared to contemporaries like Armie Hammer’s Winklevoss twins in The Social Network and Sam Rockwell and his clone in Moon. There’s usually a physical division between the two brothers - bar counters, tables etc - which draws unwanted attention to the effect, and in several scenes the eye-lines don’t quite match. Hardy gives an energetic dual performance but too many scenes evoke that classic Star Trek episode in which William Shatner faced off against an evil, goateed version of himself.

Writer-director Brian Helgeland is best known for penning the screenplay for L.A. Confidential, a movie that brilliantly conveyed a sense of time and place, making Los Angeles one of the film’s main characters. Sadly, this isn’t a feat repeated here; London is hidden in the background here, glimpsed through green-screen windows as a poorly rendered CG skyline, as artificial as Frasier’s Seattle. London was the center of the earth in 1966, a city at its cultural peak the way New York would be a decade later, but Legend may as well be set in Coventry in 1973 for all the context we’re given.

At over two hours, the film wastes a lot of time on extended dialogue scenes, telling us constantly how powerful the Krays are, but it rarely demonstrates this visually. Much of the film focuses on the doomed relationship between Reggie and his young bride Frances (Emily Browning), who provides an unnecessary voiceover narration, and if you’ve seen any gangster movie, their argumentative scenes together will feel all too familiar. A sub-plot involving Chazz Palminteri’s representative of the American Mafia leads nowhere, and feels inserted purely to help sell the movie Stateside. Christopher Eccleston pops up as the cop investigating the brothers, but this is another element that’s barely covered.

The sight of Tom Hardy attempting to out-act himself is just about enough to hold your attention for a good portion of the film, but after a while the lack of substance begins to weigh heavy and the strings become all too visible. East End? More like dead end!