Stolen opens with the legend ‘Once upon a time…’ printed on the screen. Like the fairytales that two German brothers collected and published in the nineteenth century, this is about as Grimm a story as it gets: a ninety-minute narrative concerned with child trafficking, families and – most crucially – the willingness of ordinary, otherwise decent people to overlook the horrors that exist at the edges of their everyday lives.

‘I’m not a pimp,’ Thomas Ekoku drawls as he offers Rosemary, an eleven year old girl from East Africa, to a family for a paltry five grand. ‘I’m a businessman.’ Although it’s the poor girl’s services as a housemaid that he’s offering, rather than anything more disgusting, this loathsome character (played to odious perfection by Nonso Anozie) makes pimps look like national benefactors. He’s a slaver, selling adolescents as automatons, and it’s him and his ilk that DI Anthony Carter (Damien Lewis) of the Human Trafficking Unit is pursuing, to protect Rosemary – and Georgie, the hardworking Ukrainian boy convinced his illegal move to the UK will lead him to a great job and plenty of money; and Vietnamese teenager Kim Pak, who ends up working in a suburban dope den where, thanks to the ceaseless ultraviolet light above the weed, ‘it’s always morning.’ It’s a toss-up as to which of the children’s stories is the saddest, but who are the real villains in this uncomfortably compulsive piece of television?

It’s not the gun-toting gangster with a windowless house full of potted pot plants and constantly conked-out kids like Kim Pak; it’s not the hatefully cruel Cockney in charge of the squalid squat that Georgie vainly tries to keep clean and tidy; it’s not even the detestably smug Ekoku himself. They’re all part of it, of course, but the real problem isn’t the supply; it’s in the demand. As Ekoku says, ‘It’s all the educated, greedy Europeans who gladly pay money to abuse young African girls without ever asking who they are or where they came from.’ It’s a perfectly good point – and the worst thing is that it’s not just the people buying themselves slaves who are guilty; it’s us as well.

We, the viewers, who are horrified at the notion of children being forced into foreign countries to become housemaids, or drug-growers, or dogsbodies in grimy hovels, are complicit, too. Georgie is kicked out of his squat and ends up in the streets, crying and screaming at everyone around him – all of whom ignore him as just another crazy kid, even when he ends up being knifed by a gang of passing local youths. The implication is clear: as long as the people of the supposedly civilised western world keep turning a blind eye, the traffickers will continue and the child slavery industry will flourish.

With its accusatory tone and iPhone-switching-between-apps split-screen visual style, Stolen is hard to watch on more than one level. And while the performances – particularly from young actors Gloria Ogedengebe, Inokentijs Vitkevics and Huy Pham as Rosemary, Georgie and Kim Pak respectively – are mostly excellent, there are simply too few moments of buoyancy among the bleakness (such as Kim Pak breaking through the ceiling of the dope den and sitting on the roof, shouting his delight into the blue sky, or Rosemary’s pleasure in simple mysteries she has never seen before like snow and fish fingers) to make this a comfortable enough viewing experience for the message of the script to suitably hit home.

Airs at 9pm on Sunday 3rd July 2011 on BBC One.

> Follow us on Twitter to get the latest TV news and reviews first.