Lolling on a ragged carpet in his cupboard-sized shop in the heart of old Peshawar, Wahhab the money-changer beckoned customers with a sly smile. ”Best rate,” he said, fingering a fat wad of banknotes over a low glass counter. The portly man also offered another, more discreet, service: black market money transfers, any amount, to anywhere, in almost no time.

They vanish quietly and quickly. Some are dragged from their beds in front of their terrified families. Others are hustled off the streets into a waiting van, or yanked from a bus at a lonely desert junction. A windowless world of sweat and fear awaits. In dark cells, nameless men bark questions. The men brandish rubber whips, clenched fists, whirring electric drills, pictures of Osama bin Laden.

For five years the mystery surrounding Mullah Muhammad Omar, the Taliban supreme leader, has been impenetrable. Most of the very few available photographs of him are fuzzy and indistinct. He has been captured on videotape just once. A -million American bounty on his head has gone untouched.

If Afghanistan had a tourist industry, the postcard-pretty Korengal Valley would be a star attraction. Majestic mountains soar to the heavens. Sunlight spills over terraced fields. Gleaming snow dusts the jagged peaks. But for the American soldiers stationed there, Korengal is IED Valley, a perilous, exhausting battlefield and the heart of the United States war against al-Qaeda in Afghanistan.

It was, in retrospect, an age of soft-hat innocence. At the start of their deployment to Helmand last year, British soldiers acted like preening contestants in a military popularity contest. Paratroopers spurned helmets in favour of berets, learned pidgin Pashto and armed themselves with friendly smiles.