The Edge of Love (15)

All's unfair in love and war

I've not been able to look at the name Dylan Thomas without being reminded of Kingsley Amis's verdict on the poet in his Memoirs (1991): "Thomas was an outstandingly unpleasant man who cheated and stole from his friends and peed on their carpets."

One has to allow that Amis was in his curmudgeonly old age when he wrote those words, and that he had developed an implacable hostility to the Welshman and his poems after only a brief acquaintance. It is a surprise, nonetheless, to discover quite early on that the Thomas of John Maybury's flawed but honourable drama The Edge of Love is, indeed, an outstandingly unpleasant man who cheated and stole from his friends and peed on their carpets.

Fortunately for us, the film is much less about Thomas than it is about two women who were central to his life. It presents a portrait of friendship, not a portrait of the artist. The setting is London in the early 1940s, a city of blackouts, bombs and bedsit romance. Pudgy poet Thomas (Matthew Rhys) runs into his long-lost friend Vera Philips (Keira Knightley) in a pub: he's been writing propaganda films for the war effort (his weak lungs disqualify him from service), she's a cabaret singer who entertains the masses sheltering in the Underground. They made love once, as teenagers, on a beach back home in Wales, and the flame still burns between them.

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It is fanned, oddly enough, by the volatile character of the poet's wife Caitlin (Sienna Miller), who sees in Vera a kindred spirit, albeit one not quite as nifty at performing cartwheels in confined spaces. Vera agrees to marry her admirer William (Cillian Murphy), a soldier who looks more of a poet than Thomas does, setting in motion an awkward square dance of repressed passions and untimely betrayals.

The script, by Sharman Macdonald (Knightley's mum), keeps this dance going at a sprightly pace for the first hour, and garnishes the dialogue with some fine period euphemisms: "Keep your hand on your ha'penny," is all Vera recalls of her mother's advice concerning men. With Thomas around, it was advisable to keep your hand on more than ha'pennies: a shameless sponger, the man seems never more alive than when drinking at another's expense.

Maybury's camera catches the giddy energy of the friends' saloon-bar carousing, but he also finds a visual language for the crosscurrents of tension and jealousy that crackle between them. He shoots through veils and shadows, and sometimes pauses on a face that seems to be stilled by sleep, only to show the eyes surreptitiously alert. In his close-ups, Maybury pays almost ecstatic attention to his leading ladies. I'm not sure Knightley or Miller have ever been more beautifully photographed, and they reward the director with what are, by a long chalk, their best performances. Knightley, freed from the urge to pout, lends a natural poignancy to the intense, unhappy Vera, while Miller looks ripely, raucously alive as a woman who, one suspects, was anything but likeable in reality.

Mind you, she seems a paragon next to her husband. Rhys, sounding a lot like Richard Burton, also deserves credit for playing the poet as honestly as he does: the selfishness, the disloyalty, the lechery are all there, but never cranked so high as to be completely unbearable. (The modern temptation would be to play him as a proto-rock star.) When it's discovered that he's peed on his hostess's pot plant – he and Caitlin were notoriously the houseguests from hell – he merely lolls back in bed and mutters to himself: "Naughty doggy Dylan."

Maybury has dealt before with the problem of the artist-as-lout in his haunting 1997 biopic of Francis Bacon, Love Is the Devil, but there he cleverly suggested the ways in which the life intersected with the art: Bacon shaving his face in a three-panelled mirror, or the looming profiles of Colony Club drinkers seen through distended glass. In The Edge of Love, however, there is hardly a suggestion of the art beyond a snatched line or two, making it even harder for an audience unfamiliar with the Thomas oeuvre to understand why he's so indulged. He isn't funny, he isn't charming, and, that resonant voice apart, he isn't sexy. In short, he could be any bibulous old goat in a tweed jacket.

Once William goes off to fight in Greece and the Dylan-Caitlin-Vera ménage decamps to the Welsh coast with their children, the film begins to feel very flimsy. The nervous vitality of the Blitz scenes gives way to sodden domesticity as Vera comes to realise that shacking up with the Thomases will take a spiritual as well as a financial toll. Thomas, a natural exile, suddenly looks bitter and confined in his homeland ("He hates the bloody place. Who doesn't?"), while Caitlin rages against the drudgery of motherhood and the obligation to nurture the talent of a man she loves and loathes. For all the gaiety of picnics on the beach and frolics on the shoreline, as a drama it just runs into the sand, and we get a strong impression that the interest of this particular love triangle has already been played out in London – and left there.

The script, trying to rally in the last quarter with the fall-out from William's homecoming and a courtroom trial, falls back on artificial resuscitation; it keeps moving, but it feels dead. Cherish it for Maybury's wonderful rendering of Blitz London, and for a pair of performances that will rate high on each actor's CV.

As for rehabilitating the character and work of Dylan Thomas, that's going to require a very different film – or maybe just a miracle.