Here we are in the post-summer, pre-Oscar lull, where the only thing worth watching is Legend – purely because it’s had no involvement from M. Night Shyamalan.

Legend stars Tom Hardy and Tom Hardy as Ronnie and Reggie Kray, respectively; the notorious London gangsters who controlled the East End during the 1960s. It’s essentially an ultra-violent version of Paul Raymond biopic The Look of Love starring Steve Coogan – right down to Hardy’s Partridgean performance as Ronnie, played for laughs as a cartoon psycho living in a caravan in Royston Vasey.

Clever placement of a two-star review.

Reggie, meanwhile, is a suave charmer, and it’s testament to Hardy’s talent that the twins are so distinct, both vocally and physically – even if Ronnie does look like Peter O’Hanraha-hanrahan. But the film, like the dual performance, is split into two very different parts. On the one hand, we have a glitzy, comedic crime caper; on the other hand, a serious biopic about real individuals and the lives they destroyed.

The first part – let’s call it the Guy Ritchie part – is largely enjoyable, though accusations that it glamorises its real, psychopathic subjects cannot be denied. Then there’s a mishandled lurch in tone, as the movie decides to start being serious. The film’s shallowness up to this point totally deadens any dramatic impact, because the characters are too cartoony to garner much emotional investment.

Particularly thankless is the task of Emily Browning as Reggie’s wife Frances, who narrates the film, claiming: “I was there.” Except she wasn’t – Frances is absent from most of the events she’s describing. But the omniscience of the narrator isn’t a problem; the problem is that the narration sucks. “London’s bottom had reached her top,” is the line I managed to note down, from a veritable smorgasbord of tripe.

Ronnie Kray.

Here, the blame must lie with writer/director Brian Helgeland, who previously wrote the brilliant L.A. Confidential. This feels more like Eastenders. That the film was written by an American explains the tourist-eye view of east London, full of inauthentically swanky pubs covered in not nearly enough urine, and bizarrely frequent references to tea. Because that’s what British people like.

There is a lot here to enjoy, including a great ’60s soundtrack, slick production design, and – best of all – Hardy’s brilliant turn as the funniest twins since the movie Twins. It’s seamlessly put together, genuinely making you forget that you’re watching the same man twice. But the movie drags, constantly missteps, and fails to get under the Krays’ skin; there are Carry On films with more depth than this.