Dirty Pretty Things (15)

One goody-goody samaritan and a fancy French truffle

"There's nothing so dangerous as a virtuous man," says a character in Dirty Pretty Things, and that's certainly true in drama. Okwe is a Nigerian working in London as a minicab driver and hotel clerk, but a doctor in his previous life. As played by Chiwetel Ejiofor, Okwe is the last honest man, bestriding the metropolis like a compassionate colossus. On the lookout for fares at the airport, he quips, "I'm here to rescue those that have been let down by the system," and that's exactly what the story will have him do: succour the heartbroken, defeat the unrighteous, heal the wounds of those who have had various organs untimely ripped out. Okwe's goodness could have sunk the dramatic ship, and the fact that he comes across as a believable character – a sly ironist as well as a careworn toiler – is a tribute to Ejiofor's terrific performance. He gives Okwe some weight other than the tons he carries on his shoulders.

Dirty Pretty Things is an oddity – a drama of London's underclass, an essay in multiculturalism, a bit of a state-of-the-nation essay. Its story of immigrants scrabbling for any living they can get, while trying to dodge punitive immigration officials, ought to make for pitch-black, hard-boiled drama. So it's surprising what a gently entertaining crowd-pleaser it turns out to be: the racy thriller plot about black-market organ transplants might be considered gilding the lily. This bizarre drama is from an even more bizarre provenance: writer Steven Knight is one of the creators of Who Wants to Be a Millionaire? so the script's decrying of corruption and venality looks oddly like some sort of public expiation. Some of the dialogue about the hidden dirtiness of life in our supposedly pretty capital are so on-the-nose they make you wince. When Okwe declares, "We are the people you do not see. We drive your cabs. We clean your rooms. We suck your cocks," the moment is saved by Ejiofor's straight-arrow delivery and a nicely deflating double-take from Sophie Okonedo, gamely determined to have fun with her off-the-peg role as a cheeky, knowing hooker.

Check the cast list and you see that the film is indeed the advertised departure for British cinema. Okwe befriends naïve Turkish girl Senay (Audrey Tautou), who works as a cleaner in the outwardly chintzy but fundamentally rancid hotel managed by Juan, aka "Sneaky", played by the brilliant, beefy-jowled Catalan actor Sergi Lopez. But, cosmopolitan as it is, the film is hardly a radical, of-the-moment statement, more an updated bit of Victorian melodrama. Okwe is a pauper revealed to be a prince, a doctor of good soul and absolute integrity, while Senay is the persecuted virgin, a Little Nell for our times. After she finds herself surrendering her virtue to a very bad man, a horrible, tawdry shot catches a single tear rolling down her nose.

Bizarrely, given how the film goes out of its way to be multiethnic, it nevertheless manages to sneak xenophobia and even a sort of inadvertent racism through the back door. Lopez, with slicked hair and expensively trashy shirts, gives a lovely juicy turn that's wasted on what is essentially a sneering foreign cad out of the John Buchan catalogue: they may as well sign him up as the next Bond villain now. The film's nastiest moment has Senay's virtue threatened by a predatory Asian sweatshop owner. It's just conceivable that Kriss Dosanjh's character is meant to be some sort of parody of stereotypical Bollywood baddies; if not, this is a horrifying characterisation. Given that the Muslim ingenue Senay is actually played by French actress Audrey Tautou, the epitome of asexual European niceness in the wretched Amelie, this scene looks like some misbegotten fantasy – De Sade rewritten by Le Pen. Yes, of course the film is avoiding the cliché of having only Anglo-Saxon oppressors, and so offers us equal-opportunities baddies, but even so, ouch.

Stephen Frears gets rather richer performances than the story deserves, and makes this London's claustrophobic twilight geography considerably more believable than the narrative. Shot by Chris Menges, Dirty Pretty Things is a handsomely moody package, and it plays with winning conviction that makes you forget how slender it is. And I like the idea that a sinister London black market is trading both in dodgy human offal and fancy French truffles. Could it be that, in some obscure way, the film is really an allegory of the state of British cinema?

j.romney@independent.co.uk