A British company is trying to recruit farmers to grow opium poppies to meet the urgent need to stockpile more supplies of diamorphine should its production be disrupted by an outbreak of pandemic flu. At the same time British troops are fighting and dying in Afghanistan to disrupt the Taleban’s control of the soaring opium harvest that has made Afghanistan overwhelmingly the source of heroin now flooding into Britain and Western Europe. The failure to halt this deadly trade is one of the factors fuelling the violence, impoverishing the debt-burdened farmers and entrenching the warlords and Taleban fighters in a swath of southern Afghanistan. It is, surely, also a terrible indictment of policy-makers in Kabul, in Nato capitals and in the United Nations who could transform the poppy harvest from a scourge to a blessing but have failed to do so.

Afghanistan is now awash with opium. Production has risen by around 15 per cent since 2006, with some 457,000 acres under cultivation compared with last year’s total of 408,000, according to US data. More than 92 per cent of all heroin sold in Europe originates in Afghanistan, and the proportion is still rising. Helmand province alone, where British forces are deployed against Taleban fighters, accounts for a third of the crop.

Earlier this month Britain announced an extra £22.5 million to add to the £270 million to be spent over the next three years to disrupt traffickers and their links to insurgents. But although drug-related convictions were up and six of the country’s 34 provinces were poppy-free last year, with more expected to be cleared of the crop over the coming 12 months, production elsewhere is still rising. It is this flood of opium from Afghanistan, estimated to be worth £1.5 billion annually, that has largely accounted for the global record of 6,610 tonnes last year, a rise of 43 per cent since 2005.

International efforts to stamp out this trade have had barely any effect and, in some cases, have been counterproductive. A mere 8 per cent of the total acreage was destroyed last year and crop-spraying cannot be carried out without Kabul’s permission. So far the Karzai Government has refused, and it is not hard to see why. Without counting the gangsters who dominate the traffic, opium involves 2.9 million Afghans in cultivation and another 225,000 traders – 14 per cent of the total population. Not only is the Government reluctant to criminalise so many people, but Nato is also loath to destroy the only income source for thousands of farmers, many of them tricked into becoming debtors to Taleban drug exporters. To do so would be to drive them inexorably further into the arms of the Taleban.

In a bold move some years ago, Britain tried to buy up the poppy crop, spending more than £20 million to acquire the opium and persuade the farmers to grow other crops. It was a failure: warlords snatched and resold the opium and no other crop came near to yielding the same income to the farmers. Legalising the trade for medical needs is the obvious alternative. It has been tried, with remarkable results, in India and Turkey. The need for more and cheaper diamorphine-based drugs is clearly there. The scheme is compatible with Afghan law and international narcotics regulations. It is fiercely opposed by gangsters, smugglers and the Tabeban. But it is the best way of putting them out of business.