Afghanistan's new government is failing to tackle the cultivation of opium poppies, a BBC investigation has found.

Earlier this year, Foreign Secretary Jack Straw announced that almost a third of the country's poppy fields had been destroyed.

But BBC Radio 4's Today programme found there was little evidence that the crops were being eradicated.

Most heroin in the UK comes from Afghanistan

And a bumper harvest suggests an increased amount of the drug on its way to the UK, where 90% of heroin originates in Afghanistan.

Mr Straw has congratulated the interim government on its opium eradication scheme which he said would help stem the flow of heroin into the UK.

Eradication teams go to the farms armed with sticks to destroy the opium crops.

They give farmers $350 US for about one-fifth of a hectare of poppy.

Javed Akmed is a member of the security forces and was assigned to one of the eradication teams.

He told Today: "They came here and made themselves look busy, but it didn't look like many people were taking the task seriously."

Only about 2% of the crops in the area were destroyed, he said, and documents were falsified.

Today reporter Raphael Rowe visited one of Afghanistan's major growing provinces, Badakhshan.

He said it was the same story elsewhere, with the highest figure given of 10%.

Poppy eradication earns cash for farmers

Dr Hasan Muddin, head of one of the villages, said: "Before the eradication team came, the government announced it would be strictly enforced and the farmers believed them.

"But when they came it was just a show.

"They just eradicated a few fields and gave money to a few farmers.

"The people here feel cheated and will grow poppy next year."

Dangers

A military commander said better eradication required an agreed plan with alternative job opportunities offered to encourage farmers away from the lucrative cultivation of poppies.

Sayed Tariq, governor of Badakshan, said although progress was being made, the cash incentives for eradication were counter-productive because they encouraged more farmers to grow poppy.

Raphael Rowe visited a small store which bought opium from farmers for about $300 per kg.

The opium is then sold to drug traffickers who refine it into heroin before it makes its way to Britain.

The Taleban deemed narcotics "un-Islamic"

Thomas Cronin, of the UN drugs control programme, said there could be even more heroin reaching Britain next year after a big harvest.

And Roger Howard, chief executive of Drugscope, said there needed to be a "complex response".

The rebuilding of civic institutions, better job opportunities and giving credit to farmers for growing other crops may help, he said.

According to the Foreign Office, 90% of the heroin in the UK originates in Afghanistan.

Farmers said they realised the dangers of heroin destined for Britain but the economic situation leaves them no choice.

Opium poppies have a financial yield per hectare of more than 10 times that of other crops such as wheat.

The Taleban had banned the growing of opium in areas under their control.