Leading article: The bitter fruits of neglect

The news of a record poppy crop in Afghanistan is a damning indictment of Britain's involvement in the affairs of that country. Almost five years after the fall of the Taliban, one of Britain's primary objectives for the future of that land lies in tatters. The result is that the street price for heroin in Britain - almost all of which comes from Afghanistan - is as low as it has ever been.

Naturally, the Government has a different interpretation. Ministers tell us that the real purpose of the British military presence in Afghanistan is more complex than simply eradicating poppy fields. They say that it is unfair to judge success solely by the scale of the opium crop. The stated goal is to provide security for the Afghan government and encourage local opium farmers, particularly in the south of the country, away from poppy cultivation through reconstruction projects. But this does not stand up to scrutiny. The Government has consistently given the impression in the past that one of its goals is indeed the eradication of the poppy crop. The former defence secretary John Reid argued that fighting terrorism was "absolutely interlinked" to countering narcotics.

And even by the Government's own evaluation it is failing. There is no evidence that Afghan farmers are about to switch from lucrative poppies to other crops.

This disastrous resurgence in Afghanistan's drug exports hardly comes as a surprise. The Taliban had virtually eradicated poppy cultivation in Afghanistan by 2001. But it was always likely that, when they went, opium production would return. This duly happened when the warlords, who had fought against the Taliban with the US-led coalition, seized their chance to increase cultivation after the fall of Kabul. This was the time to coax impoverished Afghan farmers away from drug production. This was the time to win the "hearts and minds" of the Afghan people. But before this could happen the attention of the world was diverted by the Bush administration's ambitions in Iraq. The Taliban have since regrouped; even they are now financed by profits from heroin.

It has fallen to British troops to sort out this mess. It seems an impossible task. On Sunday another British soldier was killed in Helmand province, the 12th to fall since Britain assumed control of the province in May.

Afghanistan has defied the influence of the outside world for centuries. It was always going to take a colossal concentration of intelligence and resources to produce a different outcome this time. In the end both were lacking. We are reaping the bitter harvest sowed by our previous neglect - not only in the wilds of Afghanistan, but on the streets of our cities.