Johnny Harris escapes the acting support card to spar with heavyweights Ray Winstone and Ian McShane in Thomas Napper's film that mixes ferocious boxing scenes with moving vulnerability.

Jawbone (15)

****

Boxing is an old man's game, where half the world champions are older than the most veteran of county cricketer. I think this may be one of the reasons why boxing dramas are so popular with movie stars: they can convincingly perform sporting heroic at an age when they'd be over the hill in anything else other than snooker and darts.

The 43-year-old Johnny Harris though is not a movie star, but after a decade and half of mostly performing on the support card, he has written himself top billing and found a select but impressive cast of name actors — including heavyweights Ray Winstone and Ian McShane — to spar with in Thomas Napper's film.

I don't know what it is about punching people with gloves that brings out the sentimental streak in men but every boxing narrative is some kind of weepie.

Harris's tale is the one about the once promising contender who threw it all away and is now homeless and alcoholic. Trying to exorcise his demons, he is making a comeback in an unlicensed, bear pit brawl.

It's a straightforward tale, but a damn good one. This is technically Napper's first film but he has an impressive CV doing second unit on big mainstream film.

He shoots it in the now standard light-pollution noir style that is the norm these days for London dramas but does it as well as anyone, capturing the dark ungentrified alleys that ripple in the murk around the base of the Shard and the other central London lighthouses.

The boxing scenes are as ferocious as you would expect.

Harris looks like an unmoisturised Jason Statham. It's a face you'd expect to have been predominantly employed snarling away in cockney gangster flicks, but there more to him than soldiers and coppers. The bristled egg menace his head projects is leavened by the heartbreaking vulnerability of his eyes.

In their supporting roles, the big names all give it their best shots in their scenes together and he stands up to them. Jawbone isn't going to make him a star but it makes you realise just how thin the dividing line is between star and support; just a few lucky friendships and breaks gotten.

His best moment comes right at the end, when he has to break down and admit his failings and it is done so swiftly and so honestly, that it is the most affecting 45 seconds of acting I've seen in a long time. It is heartbreaking in a way boxing movies shouldn't be.