The Da Vinci Code (12A)

For Christ's sake! If this movie sends a single shockwave through true believers then one can only assume that their faith rests on pathetically frail foundations. Choosing to picket cinemas that screen The Da Vinci Code makes about as much sense as picketing a Monopoly board for a perceived unfairness over property rents. Nobody has cause to worry about this preposterous confection, and that includes the studio trying to sell it: the air of hallowed secrecy thrown about the project should guarantee success for at least a couple of weeks.

Consider this instead: could anything of intellectual value or emotional excitement actually spring from the pen of the same man who wrote Batman & Robin? Akiva Goldsman (for it is he) may well have done a bang-up job of adapting the Dan Brown bestseller - I can't tell, not having read it - but what has ended up on screen is roughly as compelling as a bowl of wax fruit. The director, Ron Howard, and his cinematographer Salvatore Totino have coated its mostly night-time scenes in a kind of expensive glaze, hoping that shadowy interiors and moonlit intrigues will somehow compensate for the drama that's so lacking in its narrative.

The Da Vinci Code is nothing more than an elaborate treasure hunt pasted with lashings of Catholic doctrine, ritual and iconography. It sets itself a spurious "puzzle" and proceeds to solve it, slowly, doggedly, like someone who's forgotten the combination on their bicycle lock and tries one sequence of numbers after another. It begins in Paris, where one of the curators at the Louvre has been found murdered, his corpse scored and striped like a geometrist's notepad. Before the man expired, however, he obligingly left a series of cryptic clues addressed to his learned colleague, Robert Langdon (Tom Hanks), a semiotics professor who happens to be in town promoting his new book. No sooner has he been summoned to the crime scene than gorgeous police cryptologist Sophie (Audrey Tautou) is helping him escape the clutches of a police detective (Jean Reno) who is in alliance with Opus Dei, a Catholic cult so sinister that members talk in Latin even on their mobile phones. Horresco referens!

In the way of sinister cults, they have their own crack assassin, an albino monk named Silas (Paul Bettany) who likes to spend his downtime in frenzied bouts of self-flagellation (I told you there were lashings). He too has a mobile phone, incongruously hidden in his monk's cowl, on which he communicates to his "master". At first we assume this shady personage to be Bishop Aringarosa (Alfred Molina), a name helpfully interpreted for us in the press notes, "aringa" meaning herring, and "rosa" being red. "Does this mean the Bishop is a red herring?" people have asked. While you decide, the film makes just enough of his accoutrements - episcopal bling, private jet, opulent chambers complete with billiard table - to damn him as a vulgarian, if not wholly to implicate him as a murderer.

The dashing prof and his cryptologist, meanwhile, have fled Paris and found refuge at the house of Sir Leigh Teabing (Ian McKellen), conveniently situated some miles from the capital. Even more conveniently Sir Leigh is a world expert on the Holy Grail, and so can explain the cryptogram of Da Vinci's "Last Supper" painting and the murky theological arguments encoded within. Did I say "explain"? What he actually does is yarn a great deal about an immemorial conspiracy, sponsored by Opus Dei, to hush up the true significance of the Grail. The central tenet of this outlawed interpretation is that Mary Magdalene was Christ's wife, and that she was supposed to be the one to continue His church.

Well, it might not be "the greatest cover-up in history", but it's not uninteresting as a theory; unfortunately, it comes hedged around by so many complications and caveats that in the end you can barely make it out. The Knights Templar; The Witch's Hammer; The Priory of Sion; The Council of Shadows: these are just a few of the names portentously intoned to suggest what a deeply inscrutable Code this is, but what the eye might slide over in Dan Brown's book becomes, up on screen, an increasingly dour and dreary gabfest. This may be the talkiest blockbuster ever made and, while it exists on a slightly higher plane of intelligence than George Lucas, it partakes of the same long-winded intricacy as Star Wars. At times the film-makers seem to wake up to the fact that there's too much talk and not enough action. Their solution is to contrive a number of tight spots for Hanks and Tautou, then simply apply the old formula, "with one bound they were free". A child improvising an adventure story could manage something more gripping.

Ron Howard and his producers decided not to hold test screenings of the film, a bold and virtually unprecedented step that might yet rebound on them. It's not simply that The Da Vinci Code is difficult to understand - Hitchcock made trickier movies than this and still seduced audiences. But he understood that a mystery thriller doesn't have to be credible, it just has to be convincing. Howard and Co haven't really got a clue, and their attempts to meld cerebral concerns with thriller imperatives sometimes come a terrible cropper. At one point, when the scene has switched to London, hero and heroine stop on a street. Hanks says, "I need to get to a library - fast", an exquisitely boring line that's made ridiculous when the pair of them then board (wait for it) a London bus. Yes, that should get them there fast. No need to worry, though, because on the top deck they can consult a stranger with a Blackberry-type gizmo that accesses all the info they need.

As for the performances, you couldn't call Hanks and Tautou a charismatic pairing. He wears his hair in a kind of stunted mullet, while his features barely deviate from a waxy unease; Tautou is distractingly pretty but wooden, and delivers her lines on a single note of petulance. Then again, they've had to cope with a script that would squeeze the life out of anyone's performance: the two basic expressions required are brow-furrowing bemusement and reverential awe, the latter supplied in full measure by Hans Zimmer's overwrought score. The real wonders of the Catholic faith end up here in much the same condition as they do in every Hollywood movie - as schlock. Hardly the Devil's work, I suppose, but nothing to be proud of, either.