A local Taleban commander in Afghanistan has promised to inflict a massive defeat on British forces there.
Mawlawi Amira Hamza al-Ghazi said it was his fighters' Islamic duty to defeat the enemy.
"We have to give them a teeth-breaking defeat again," he told the BBC in an exclusive interview.
The Taleban commander's group is based in the southern province of Helmand, where more than 3,000 British soldiers are currently deploying.
Helmand is one of Afghanistan's most dangerous provinces, and a centre of Taleban activity. It produces 20% of the world's opium.
British soldiers replaced US forces in the area as part of an expansion of peacekeeping operations by Nato at the start of May.
The British commander in Helmand, Col Charlie Knaggs, said he was convinced the Taleban had been put under severe pressure by the international forces there.
A soldier with the parachute regiment's elite Pathfinder unit told the BBC's defence correspondent Paul Wood that they had killed some 30 Taleban insurgents since arriving in Helmand three months ago.
Our correspondent says people in the towns do not seem to support the insurgents. But one British soldier told our correspondent that he felt there was more support in the region's countryside.
'Plans for the enemy'
Mawlawi al-Ghazi was with 50-70 fighters - armed with automatic weapons and rocket-propelled grenades - when he spoke to the BBC's Pashto service in Afghanistan.
The Taleban fighters said they were just leaving on an operation against the enemy - the enemy being British soldiers and Afghan security forces.
"It is our Islamic duty... we have plans for the enemies. All Muslims, local and international, are supporting us," said their commander.
"We have advanced equipment to use against them. Throughout our history we have defeated them many times, but they do not understand."
Asked why they were fighting, Mawlawi al-Ghazi said US President George W Bush and UK Prime Minister Tony Blair wanted to destroy Islam.
"It is the order of our commander, [Taleban leader] Mullah Omar, that we must fight against these people... He is alive and we are all under his command."
British forces are in southern Afghanistan to help the newly-formed Afghan National Army (ANA) fight the increasingly violent militant groups based around the Pakistan border and curb the drugs trade that funds them.
Violence has shot up in recent months.
About 900 people have been killed in the insurgency since the beginning of this year - half have died in May alone.
The number of suicide attacks recorded in Afghanistan has also risen sharply since the US-led invasion which toppled the Taleban in late 2001.
Foreign troops, pro-government clerics and officials and mosques have all been targeted.