Biopics are a much maligned category of film … with good reason. Despite the preponderance of such films – only, ultimately, connected by being about ‘someone dead and famous’ – there are surprisingly few great biographical films. There are a lot of ‘entirely fine’ ones, but I can only think of handful that could be genuinely regarded as excellent: Amadeus, Raging Bull and, of course, Walk Hard: The Dewey Cox Story.

It was therefore with some degree of trepidation that I sat down to see Mr Turner, Mike Leigh’s portrait of the last couple decades of the life of British artist J. M. W. Turner, despite its pedigree (Leigh, obviously, plus Timothy Spall’s Best Actor award at Cannes in the lead role). The trailer (which plays before every film at the British Film Festival including this one) promises an entirely conventional story of a misunderstood, misanthropic visionary unappreciated during his time and so on and so forth. Thankfully, while Mr Turner doesn’t exactly achieve greatness, it clears the hurdle of ‘boring clichéd biopic’ with ease.

Spall deserves much of the credit for elevating a role that could have easily slid into caricature in less capable hands. He wanders around with a perpetual scowl and his dialogue is so dominated by snorts, grunts and growls that he might as well have been dubbed by a barnyard. Turner is a curmudgeon and a right bastard – the way he treats his maid or the mother of his children makes Johnny Cash in Walk the Line look like a saint – but Spall is simply interested in portraying his humanity. It’s a complex, impressive performance, providing insight into the man’s genius without smoothing over his abundant shortcomings as a man.

The rest of the credit, of course, lies with Mike Leigh. I’m only new to Leigh’s oeuvre this year, but after seeing a handful of his films I’m beginning to see trends in his work beyond his improvisational, collaborative approach to cinema. He tends to split the difference between the purposeful and the organic from scene-to-scene, somewhere in the middle of natural and theatrical. Something like Secrets & Lies threatens to be boring and eventless until you realise how deeply you’re invested in its characters; he’s perfect, then, to produce a biopic. He avoids the typical flaws of the genre by choosing scenes that inform mood and character rather than checking off Wikipedia dot points or awkwardly strapping real-life to a three act narrative.

Mr Turner is essentially plotless, as with much of Leigh’s work. Equally, it doesn’t slot neatly into a genre beyond the broad category of ‘biographical film.’ It’s often comedic, but hardly a comedy. The film has its dramatic moments, but it’s not precisely a drama, either. Topsy-Turvy, Leigh’s 1999 period piece on Gilbert and Sullivan, was less a biopic than a presentation of what it takes to put on a huge musical production. Mr Turner intermittently threatens to become a painting procedural – meetings with clients and the like – but it never really commits to this conceit. It’s arguably a character study, but I’d argue it’s more interested in simply observing Turner than studying him.

It’s an impressive film that can demonstrate such certainty in its approach – and a divisive one, likely to provoke the same range of reactions as Turner’s formal experiments late in his career. Those looking for insight into Turner’s art or a more traditional story about the man are likely to be disappointed – and it is, ultimately, a touch too aimless to attain greatness. It’s astoundingly beautiful – it’s the first time I’ve really felt able to describe Leigh as an aesthete, his compositions and colouring here obviously inspired by Turner’s brilliant paintings – and commendably absent the clichés that drag down its biopic counterparts.