The Afghan National Police Special Task Force received a tipoff about a stockpile of drugs located about 40 kilometres from the Pakistan border in Kandahar Province.

They found the cannabis hidden in several trenches, and destroyed the drugs in situ that day by setting fire to the trenches.

The destroyed cannabis had an estimated wholesale value of US$400 million (£200 million).

Nato-led forces in Afghanistan heaped praise upon the Afghan police for their efforts.

"The Afghan National Police Special Task Force has made a huge step forward in proving its capability in curbing the tide of illegal drug trade in this country," said General David McKiernan, commander of Isaf, Nato's International Security Assistance Force.

"With this single find, they have seriously crippled the Taliban's ability to purchase weapons that threaten the safety and security of the Afghan people and the region."

"The international community will continue to support the Afghan forces with more of the same training and support that helped them achieve such success in this mission."

Afghanistan has been criticised in the past for failing to crack down on drug trafficking -- the success of this operation will go a long way to improving their reputation with the international community.

"This was the largest ever single find of narcotics in history," said David Miliband, the UK Foreign Secretary.

"It reflects the efforts of the Afghan government against the drug trade, and was so large that two aircraft were brought in to destroy the underground bunker in which the hashish was being stored."

"Britain and the rest of the international community will continue to do everything we can to support the Afghan government fight the narcotics trade, and promote Afghan development."