The Da Vinci Code (12A)

Holy blood, Holy Grail... unholy mess

The Vatican, Opus Dei and the Greek Orthodox Church have all been up in arms, while Catholics in Mumbai have threatened to starve to death if The Da Vinci Code is released in India. Here in Cannes, where the film opened the festival on Wednesday, critics can only admire the conviction of the Mumbai demonstrators; most of us would happily have seen the movie pulled, but grudgingly sat through it without so much as giving up a plate of bouillabaisse in protest.

It's strange to imagine that a film co-starring Audrey Tautou could be considered improper, let alone heretical. Who'd ever have figured that nice Amélie as the Whore of Babylon? I was rather hoping for a scene in which she discovers the face of Satan leering out from under the crust of her crème brûlée. Anyway, there haven't yet been riots on the Croisette over the film, apart from a contingent of persistent nuns hovering forbiddingly outside the Palais.

So is the film better or worse than Dan Brown's best-seller? Worse. At least you can throw the book out of the Eurostar window; with the film, you're trapped for two-and-a-half hours. Those of you who haven't read the novel, you can both turn away now in case I spoil any of its twists. But Akiva Goldsman's adaptation is pretty faithful to the original plot, in which an American academic is thrown into a whirlwind search for the Holy Grail, which isn't actually a Grail at all, but something far more portentously mystical. The academic is Tom Hanks, glumly one-note in scraggy hair, and he's joined by a robotically stiff Tautou as a French police cryptologist (I suspect Brown thinks this means an expert on crypts), whose art-historian grandfather has been found dead in the Louvre. The old man, a bit of a wag even in extremis, has scrawled enigmatic clues to send Hanks and Tautou to the next stage of their search for truth: the Grail quest re-imagined as a fancy Easter egg hunt.

The seekers are aided by Ian McKellen's testy, tweedy Grail expert Sir Leigh Teabing - an eccentric gentleman amateur so fabulously wealthy that he has a private plane for whizzing off to sniff around Templar churches when the mood takes him. In hot pursuit, meanwhile, are Jean Reno's copper and a glowering Paul Bettany as albino monk Silas, whose naked sessions of self-flagellation and chastisement by spiked garter are so gloatingly shot that you suspect the film is partly aimed at those people who use The Passion of the Christ on DVD as homoerotic soft porn.

A book whose stupidity follows you around the room, Brown's novel is an inept mess, and an insult to its target readers, middle-aged residents of Akron, Ohio who may be considering a first visit to Europe. Screenwriter Akiva Goldman, who possibly cheated by using joined-up writing, nevertheless maintains the dialogue's authentic Brownian fizz and snap ("The Vitruvian Man! It's one of Leonardo da Vinci's most famous sketches!").

The plot, about a plain chap suddenly whisked off on a breakneck caper, is basically North By Northwest with a rucksack-full of unreliable historical guidebooks. All that stuff about the Knights Templar, the Priory of Sion and Leonardo's female symbolism makes for a whole mess of exposition to wade through, which explains why Hanks looks throughout like a man anxious to return to his hotel room for an interrupted crap.

Howard tries to liven up the talkiness with some visual frills. He has McKellen talk us through The Last Supper with a set of snazzy digital illustrations, so that the film starts feeling like a long, expensive Powerpoint presentation. Brief but insanely lavish historical reconstructions also burst into life on the screen, with thousands of knights besieging Jerusalem before your eyes in little Cecil B DeMille bites.

"I'm into something here that I cannot understand," Hanks says at one point; he could almost be airing his director's sentiments. Breathing any life into this nonsense is way beyond Ron Howard, one of Hollywood's more stolid journeymen. Howard can't handle either the Gothic creepiness or the Hitchcockian derring-do, and his lack of control over his material comes to a screeching head in a showdown between cops, Silas the monk, and Alfred Molina's Spanish cardinal - a scene that might almost have been slipped into the film by Pedro Almodóvar as a prank. Apart from such little sparks of absurdity, The Da Vinci Code is simply the dullest, most pedantic blockbuster of recent years. Never mind mortification of the flesh, see this and you'll know what it is to mortify the brain.