Don’t know about you, but whenever I go to the theatre to see a Shakespeare play, it always takes me a good ten minutes to understand even the very basics of what the characters are saying. I need to ‘tune in’ to the challenging vocabulary, cadence and rhythm of the strange-sounding verse. And then suddenly I do, all becomes clear (well, nearly all) and we’re away.

I mention that because something similarly unsettling happens at the outset of Kenneth Branagh’s new film about William Shakespeare, 'All Is True'. Not because the language is challenging – with Ben Elton supplying the screenplay, it commendably is not. But little else rings true, at least initially.

The re-creation of the burning down of the Globe Theatre in 1613, which sent Shakespeare into premature retirement and scurrying back to Stratford-upon-Avon, is unconvincing, as are the visual effects recreating 17th-century rural England.

Then there’s the extraordinary appearance of Branagh himself as the Bard, who is all hooked nose, domed forehead and unlikely-looking facial hair. No one knows what the great man looked like, of course, but something more ‘real’ and less distracting would have been a better start.

Then, with Branagh directing as well as starring, we reach Stratford and discover that Judi Dench is playing not Shakespeare’s mother but his wife, Anne Hathaway. In real life, Anne was eight years her husband’s senior but Dench – who really has played Branagh’s mother on stage – is 26 years older than her male co-star. Hmm.

Throw in a directorial style that embraces stillness, darkness and the sparse use of music, and you have a film shaping up to be an uncomfortable and occasionally even annoying old watch. Another 'Shakespeare In Love' this clearly is not.

But slowly it all begins to come together, helped by spirited performances from Kathryn Wilder and Lydia Wilson, who play Shakespeare’s daughters, Judith and Susanna; the welcome arrival of some humour to leaven the gloom; and by the fact that Dench remains hugely watchable whether she’s playing 60 or 160.

Although his appearance remains a distraction throughout, Branagh is pretty good too as Shakespeare turns his talents to, er… gardening.

What emerges is an ambitious attempt to turn the older Shakespeare into a real man by exploring the juxtaposition between creative genius and human fallibility. Or to put it another way, how the writer of some of the greatest plays the world has ever seen could still have a family life that was a mess.

Anne won’t forgive him for effectively deserting her (her husband spent most of his working life in London). His son, Hamnet, died supposedly of the plague aged 11. And as for his daughters – Judith is now an angry spinster of 28 while Susanna is married to a religious puritan who wants to close down the theatres.

It must be emphasised that what Branagh and Elton (here very much in non-Blackadder mode) have constructed is essentially a work of fiction that takes some of the few facts known about Shakespeare (Hamnet’s death, his own retirement, his famous leaving of his ‘second best bed’ to Anne) and constructs a plausible, interesting and eventually rather moving narrative around them. But a narrative that almost certainly isn’t true.

It all smacks, rather entertainingly, of the sort of conversations that actors must have been having for hundreds of years, after a performance, once they’ve finished with the sniping and the gossip and settled down with a glass or three to reflect on the essential unknowingness of Britain’s national playwright.

Here, he is portrayed as an artist who believed that nothing was true until a writer looks deep into his soul (it’s tempting to automatically add the words ‘or her’, but Shakespeare is shown as a victim of his sexist times) whereupon, magically… Well, the film’s title tells you the rest.

The end result is not entirely coherent, retaining an episodic quality that does slightly diminish the film’s impact.

As a storyline, Susanna’s possible infidelity peters rather disappointingly out, while the sudden appearance of Sir Ian McKellen, in magnificent blond wig, as an ageing Earl of Southampton (to whom Shakespeare dedicated his early sonnets) provides the sort of comic interpolation that Shakespeare plays often require when the scenery needs to be rearranged. It’s also unfortunate that a key storyline involving Judith has been well covered by a handful of other films recently.

But the damage is minor. All’s well that ends well. Eventually.