Hard road to Kilburn

The three words of the title have a sinister ring as well as a plain meaning. "In this world" means "alive". Death, or even its possibility, is never mentioned by name in the whole of Michael Winterbottom's new film.

Yet it is everywhere "in this world" where two young Afghans try their luck and risk their lives on the road from Peshawar to Kilburn. It would not have been a better film even if it had been a better-made film.

In its very roughness lies its integrity. Though Tony Grisoni is credited with "the script", it is difficult to believe that a word spoken by 16-year-old Jamal and his older cousin Enayatullah, two non-professionals, was ever written down; or that anything that happens on their odyssey was ever foreseen by producers Andrew Eaton and Anita Overland.

The same sort of covert digital camerawork (by Marcel Zyskind) that has revitalised Iranian cinema, catching daily life under tyranny on the sly, permeates this story with impromptu truth. Jamal is a brick-maker, chubby, trusting, hopeful and (best of all) young. Ena is a market-stall keeper, thin, pessimistic and experienced.

There is not much else to know about them, for there is not much else they have: their ambition to reach London seems absurdly disproportionate to their means - and sheer madness in terms of distance to be travelled.

They are seen off from the Pakistani refugee camp after the usual money-changing with " people managers", then passed from hand-out to hand-out, their dollars diminishing with each palm that needs greasing or each frontier requiring new currency. The colour of money, though, isn't as pervasive as the colour of sand. This is Central Asia without the beauty spots, an itinerary once glorified by the name The Silk Road. Human merchandise is now its freight, and it comes in one colour only.

To create tension, the film-makers rely on anxiety, not drama; but the two sometimes meet. An Iranian border guard looks like stalling their progress until Jamal slyly slips him Ena's Walkman. Sony technology is the new open sesame. But then an officious Turkish cop boards the freedom bus, and lo! the pair are whisked back to square one quicker than on a magic carpet.

They start again. Though they get help from those no better off than the/ mselves, the scenes with most impact are not the ones of hospitality, or incredibly happy children (a Winterbottom weakness) at play in the backyard of beyond, but the inhospitable presence of bureaucracy guarding this great swathe of Central Asia as if Genghis Khan's writ still ran.

By far the better two-thirds of the film happens in this hinterland, where snow and darkness reduce even the camerawork to a matter of guesswork. Ironically, it is when the pair finally leave the Orient, stowing away in the hideous compress of hidden human cargo aboard a Trieste-bound container ship, that Winterbottom's film begins to suffer the same breakdown in communications as the two migrants - though never as fatally.

In retrospect, it's easy to see what remedy was required: where everything up to this point has allowed humanity to draw the story together, from here on officialdom should have featured more divisively as the couple make landfall in Europe only to discover even more illiberal barriers that won't take a Walkman as a laissez-passer. We badly want to know the details of refugee experience on our own doorstep. We're denied them; though an episode in Sangatte suggests the tantalising nearness of achievement that must have ached in migrant hearts.