Films: The Big Picture - A large blue feather to tickle our sensibiliti es

There should be another term by which we might describe film adaptations of novels that drastically reinterpret the source text. With a picture like The Wings of the Dove, the credit "based on the novel by Henry James" just isn't appropriate - it suggests an almost logical progression, as though the ideas and themes contained within the novel were being taken up by the screenwriter in a kind of literary relay race, which patently isn't the case. "Inhabited by the novel by Henry James" would be nearer the mark. You couldn't argue that The Wings of the Dove was faithful to its source in any conventional sense, though it displays another sort of loyalty - it feels like a dream about James's novel, rather than an adaptation of it, which is perhaps the only sensible way for a film-maker to approach this most famously interior of writers.

The director Iain Softley (see interview below) specialises in films about little surrogate families - he made Backbeat, which depicted the early days of the Beatles, and Hackers, a light comedy about a renegade band of computer nerds. It should be a credit to those earlier pictures, rather than a slur on The Wings of the Dove, to say that Softley treats James's trio of tortured souls with the same breezy generosity that he dished out to Lennon and Co, or the cyber-boffins. He has a loose, discreetly daring style that won't upset those viewers who have come to marvel at the posh frocks, but which contravenes the polite objectivity of the traditional costume drama all the same.

Sometimes he can jolt you out of your seat with a single well-timed effect - a soccer ball falls toward the camera, which then switches position to watch it complete its journey to earth; in another scene, two women leaf through pornographic books, and as Softley zooms in on the crude illustrations, their cheeky snickers grow obscenely rambunctious until you realise that it's actually the premature laughter of the party guests in the next scene that you can hear. The use of sound is also subtly unnerving during a Venetian carnival scene, where the camera prowls across the water, surveying a traffic jam of gondolas in which figures in death masks huddle in the darkness, while the soundtrack comes alive with an urgent percussive rhythm that sounds like a bag of bones being rattled. You can feel Softley's delight in unnerving his audience, though he doesn't always try for a sinister effect - early on, there's a lovely comic edit which is very nearly a Godardian jump-cut, where Kate Croy (Helena Bonham Carter) is standing in her lover's doorway one moment, and is sprawled across his bed the next. "Gagging for it" might not be a phrase that cropped up in James's novel, but it's practically flashing in neon above every character in the film.

The picture shifts the action of the novel forward by eight years to 1910, which gives Softley the chance to pull off two key scenes whose visual potency rests on locations and props specific to the era. The film opens in a seedy London Underground carriage, where a cluster of murky brown suits and bowlers is interrupted by the blue plumage on Kate's hat. It may be that this bold effect is only a whisker away from having Kate trot in wearing a platinum wig and a badge proclaiming "Femmes fatales do it in stilettos", but the brashness feels thrillingly rude and devilish.

If Kate's entrance doubles as a statement of intent from Softley, then what follows feels as if he and his screenwriter, Hossein Amini, were scribbling graffiti in the margins of the novel. Kate tempts her lover, the journalist Merton Densher (Linus Roache), into an elevator, where their clinch immediately punctures that taut sexual tension that is characteristic of James. As you watch Kate and Merton writhing behind the lift's iron shutters, it becomes clear that Softley and Amini are not prepared to be coy about the extent to which these characters are trapped by passion. The film is full of images of imprisonment, self-imposed or otherwise. There are repeated shots of Merton being denied access to a woman who remains ensconced in her chamber - at the beginning of the picture, he is turned away from Kate's door on the orders of her aunt, who wishes her to wed a more respectable suitor, as Kate watches from her window; later, he receives the same treatment when he arrives to visit Milly (Alison Elliott), the dying American heiress with whom he has travelled to Venice as an unwitting pawn in Kate's get-rich-quick scheme. One of the final shots is of Kate curled naked on Merton's bed, an image which might suggest rebirth if it weren't filmed through the bars of the bedstead, transforming Kate's sanctuary into her prison.

There has been a considerable attempt made to blunt the abrasive edges of Kate's personality, though it is to the credit of Helena Bonham Carter that this is not entirely convincing. The screenplay often seems to be preoccupied with fulfilling PR duties on Kate's behalf, but Bonham Carter secures your attention, and even affection, without necessarily being likeable.

She is lit like a skeleton, the severe angles of her cheekbones carving through the stark white light that falls on her face. Even before Kate explicitly reveals her plan to unite Merton and Milly, so that she and Merton may benefit from Milly's will, her most apparently charitable act has an unsavoury lewdness about it. Having learnt the art of matchmaking from observing the military manoeuvres of her aunt, Kate deposits Merton and Milly in front of Gustav Klimt's Danae, as though the painting itself might act as an aesthetic aphrodisiac. The scene has only been made possible by the screenplay's shift in time - Klimt did not complete the painting until 1908 - but it works against the film's idea of Kate as essentially sympathetic, and actually brings the character closer in line with James's conception of her. The choice of this painting is significant on an immediate level because of the striking resemblance that the flame-haired actress Alison Elliott bears to Danae - it is as though Kate were inviting Merton to imagine Milly stripped and lost in desire like Danae, even as the timid Milly herself looks on oblivious, a pathetic gooseberry in her own seduction.

`The Wings of the Dove' (cert 15) is on general release from today.