Lovely lads. Only ever harmed their own. Etc

Stephen Hawking and the Kray twins might not be obvious bedfellows, but there is a slightly tenuous comparison (not the last of those in this post) to be made between Brian Helgeland's Legend and Oscar-tastic Hawking bio The Theory of Everything. Both are based on accounts by the protagonist's spouses, with the male heroes/villains being mostly seen through their eyes, in case you were wondering. Neither Ronnie nor Reggie had a hitherto-unknown interest in astrophysics, as far as I know.

Emily Browning narrates the film as Frances, a fresh-faced East End girl looking for a way out, who is seduced by 'normal' Kray brother Reggie at the start. We are then taken on a gleeful whistle-stop tour of the Krays' manor-cum-empire, including a childishly exciting tit-for-tat feud with Sarf London's Richardson family, and Reggie's club where celebrities and aristocrats enjoy the frisson of rubbing shoulders with members of the underworld.

This opening part of the film brings to mind standard post-Lock Stock Brit gangster fare in the way it indulges in comical banter and cartoonish violence, but Helgeland's script and direction are way too smart to slide into total cliche. He portrays the supeficial glamour of the twins' lifestyle, but as Frances quickly learns, the seediness and pettiness of this world is never too far below the surface. And it's also an utterly parochial one, with visiting Vegas mobsters looking impossibly glamorous in comparison to the twins' grizzled East End associates.

And so to Tom Hardy. If this were a lesser firm and a lesser actor, this dual performance would be stunt casting of the worst kind. Instead, Hardy creates two distinct characters who are nonetheless two sides of the same coin, inextricably bound to each other. Through his effortless charm and mild geezerish tones, Hardy's Reggie brings to mind TV's own Dermot O'Leary (yeah, I went there). Meanwhile, he plays brother Ronnie - paranoid schizophrenic, psychopathic, owner of pretty much the full house of mental disorder bingo - as a hulking, brutish idiot savant, a man impossible to predict because even he doesn't seem to know what he's going to do from one moment to the next. Both performances are riveting.

When the story of Reggie and Frances's relationship takes more dramatic turns later on, the film does get slightly bogged down and loses some of its earlier vigour. It's of course necessary to have a strong story, and it pleasingly shies away from simple cops'n'robbers plotting. But we never really quite get under Frances's skin - she is just a simple girl seduced by the charm of a man who represents an escape route from her old life, who realises too late the cost of her new one. Maybe that's the point.

I would have welcomed further examination of the bond between the brothers and their wider family. Mrs Kray only appears fleetingly, which presumably was a deliberate decision due to this Dear Old Mum angle being well-trodden ground. But for the majority of Legend, Hardy and Helgeland do a fine job of making a time-honoured genre and a familiar real-life story feel thrillingly fresh.