The Taleban could earn £50 million from another bumper crop of opium in Afghanistan this year despite the presence of British troops in its main production zone, a United Nations survey said yesterday.

Afghanistan, which produces 90 per cent of the world's illegal opium, is also expected to increase its output of marijuana, according to the survey by the United Nations Office on Drugs and Crime (UNODC).

The survey showed that opium output was expected to drop in northern and central Afghanistan, but it would continue to rise at an “alarming rate” in the insurgency-hit south and southwest, and could exceed last year's crop, which accounted for 78 per cent of Afghanistan's total cultivation.

Afghanistan cultivated a record 193,000 hectares (477,000 acres) of opium in 2007, a 14 per cent increase over the previous year. Total production, boosted by unusually high rainfall, rose by an even faster 34 per cent.

“Opium cultivation in Afghanistan may have peaked, but the 2008 amount will still be shockingly high,” Antonio Maria Costa, the head of UNODC, said. “Europe and other major heroin markets should brace themselves for the health and security consequences.”

Rangeen Dadfar Spanta, Afghanistan's Foreign Minister, said that his country was determined to reduce poppy production by 25 per cent this year. “Afghanistan believes we have only one choice,” he said. “Poppy can destroy us or we destroy the poppy.”

Times Recommends

• The Japanese Prime Minister is doomed: or is he?
• Brighton company 'involved in cyber attack'
• The art of survival: it’s all in the mind