Charlie and the Chocolate Factory (PG)

He likes it dark. And very, very bitter

Has any popular film-maker ever matched Tim Burton's obsession with remodelling the world in his own image? Nearly every one of his films comes across not merely as a veiled self-portrait, but as a capsule case history, even a cry for help. This is particularly true of Charlie and the Chocolate Factory, an extravagant adaptation of the Roald Dahl children's book. You expect Burton to be dark and Dahl to be jaundiced, but Charlie is disturbing in a way that exceeds the sum creepiness of its two originating geniuses. The strangeness begins with the opening images of Willy Wonka's chocolate works - an oppressively dark-chimneyed citadel within which relentless machinery cranks out sleek brown slabs, wraps them with the Wonka brand, then sends them out into the world in ominous red vans.

What to make of this grimly impersonal, totalitarian-tinged production line, and of the traumatised misfit (Willy Wonka, I mean) who lurks at the controls? Ostensibly a candy-striped pleasure ride, Charlie is a quintessentially neurotic Burton angst-trip, which sees the director agonising over his situation as overseer of this multi-million-dollar digital-effects enterprise. In the figure of Wonka, Burton implicitly paints himself as the unhappy operator of a huge entertainment machine, who'd rather be a hands-on artisan, delicately snipping and chipping away at his creations like Edward Scissorhands at his ice sculptures.

Burton's Wonka (Johnny Depp) is a troubled man - an olympian genius reduced to giving the punters a theme-park tour of the inside of his head. He bears the emotional scars of a dental-abuse survivor, whose castrating orthodontist father (Christopher Lee) forbade him sweets as a child and wrapped his head in a metal brace. Confectionery becomes the adult Wonka's consuming fetish, although he's obsessed with making sweets rather than tasting them. His factory - part glacial sci-fi metropolis, part monstrously organic psychedelic fairground - exudes an uncontrollable outpouring of hysterical over-productivity. It's no fun, Burton seems to lament, having so many ideas, and such lurid ones.

The cod-therapeutic back story is the addition of Burton and screenwriter John August, but the film's substantial strangeness comes direct from Dahl's book. The cautionary-tale sternness remains alarming, with four out of the five child visitors to Wonka's factory having their moral flaws corrected in terrifying, aggressively punitive style.

Spoilt Veruca Salt is assaulted by a pack of squirrels, while Mike Teavee is teleported into mini-remakes of 2001 and Psycho. Their fates are given an additional sting by the menacing, smugly vindictive musical routines of Wonka's hirelings the Oompa-Loompas (a virtuoso performance, or performances, by Deep Roy, digitally multiplied a millionfold). Even when pushed into the realm of broad parody, though, there's still something unpalatable about Wonka as a colonialist speculator importing a workforce of Asian pygmies and paying them with cocoa beans.

Visually, the garishness sticks to your eye like toffee to a molar, Alex McDowell's hip-kitsch design evoking less a coherently fantastic world than a set of exotic clashing environments. The most inspired is the simplest, Charlie Bucket's house, literally a lean-to, in which his immobilised grandparents live four to a bed (an arrangement that's less Bucket than Beckett). Burton's typically cartoonish-looking cast - including the genially larky likes of David Kelly, Noah Taylor and the fearsomely-jawed Missi Pyle - is offset by the placid, old-fashioned normality of young Freddie Highmore as Charlie (so politely, eagerly earnest that he'd make a perfect lead for Tony Blair's Schooldays).

The whole film founders rather on the wildly ostentatious oddness of Depp's dandy candyman - a child-like, feminised figure whose doe eyes, bangs and digitally retouched smooth skin make him unnervingly resemble Audrey Tautou in Amélie. A neurotic, paranoid recluse, dispensing off-colour hipster one-liners, Depp's Wonka is less Michael Jackson, as has been suggested, more an amalgam of Howard Hughes, Ronald McDonald and the Great Oz, as played by Pee-Wee Herman in Prince's mid-Eighties wardrobe. Twinkling and charismatic as he supposedly is, Willy Wonka is not easy to like, with his distracted and menacing lack of empathy for his guests, not to mention his scandalously lax standards of industrial safety.

Just because Charlie is laden with neurosis, however, doesn't mean it has soul. The film's bizarre subtext is that a fun factory - for which, read Hollywood - is really a soul-destroying place. In the context of a children's summer blockbuster, this is no doubt a profoundly subversive message, but it doesn't make Charlie and the Chocolate Factory any less laboriously joyless. Ultimately, Burton's film provides as much negative publicity for pleasure as it does for dentistry.

j.romney@independent.co.uk