After a gruelling introduction to a fiercely disheartening world full of anger and disharmony, this story of two boys scrounging for scrap metal becomes surprisingly and unbelievably tender. Working in the long tradition of British social realism, director Clio Barnard pulls us into the heart of this story - loosely based on a children's tale by Oscar Wilde - thanks to the extraordinary performances she builds with her young, first-time actors.

Arbor (Conner Chapman) and Swifty (Shaun Thomas) are two boys from troubled backgrounds in the industrial wasteland of Northern England. The fearless Arbor suffers from ADHD and seems to fight his way through his cheerless world, his petulance belying a deeper passion to achieve. Everyone thinks he's a bad influence on Swifty - a far gentler lad who loves horses and who acts a protector for his scrawny best friend.

When their antics result in both of them being banished from school, the two decide there's money to be made scavenging scrap for ruthless metal merchant Kitten (Sean Gilder). Seeing an opportunity to profit, Kitten rents them a horse and cart, inadvertently giving both boys something they need. But, with Arbor's propensity to push too hard, too far and without thought of consequence, you sense their freedom is only headed for tragedy.

If you are familiar with the work of Andrea Arnold (Fish Tank), Lynne Ramsay (Ratcatcher), or the master of British realism, Ken Loach (Kes) then you know the kind of contemporary cinema Barnard is creating - the emphasis on exploring troubled working-class characters in a deeply authentic way.

Her triumph here is how we end up feeling so much for Arbor, who does so little to win our empathy. Slowly Barnard forces you to shed any bias and love this young person on the most fundamental human level.

The supporting cast of adults are flawless - from the knowing portrayal of the selfish Kitten by Gilder, to the touching performances of Siobhan Finneran and Rebecca Manley as the boys' mothers. There is always dignity at work as these women try their best to at least love their children, even if influencing them has become beyond their ability. And, while the subject matter is frequently tough, Mike Eley's cinematography is as beautiful as you will ever get for the genre.