SAS played a key role in the advance of the Northern Alliance, says Hoon

British troops played a "very significant" role in the disintegration of the Taliban and advance of the Northern Alliance forces in Afghanistan, the Secretary of State for Defence, Geoff Hoon said.

The forces, mainly from the SAS, are on the ground alongside American troops, liaising with the Alliance forces and helping to plan their offensive. The Defence Secretary said: "They've played a very significant part, introducing consistency between the bombing and the movement on the ground."

Mr Hoon denied any difference between himself and Downing St over whether the Northern Alliance should be allowed to capture Kabul.

He was quoted at the weekend as saying: "I would be quite happy to see the Northern Alliance steam across northern Afgha- nistan and take Kabul."

However, both George Bush and Tony Blair have stressed that the Alliance has agreed not to take Kabul amid fears of a bloodbath if they do so.

"There was no confusion," Mr Hoon declared, insisting he had not said the Alliance should take the Afghan capital.

"I said they should move on Kabul which is exactly the line we have taken all along. Our strategy all along has been to put the Taliban under pressure," he said.

"The Northern Alliance had generated a 'tremendous momentum' on the ground but it was 'too soon to judge' whether they would regroup around Kabul or further south.

"The speed of the collapse of the Taliban in the north had come as a surprise. But that was something we always thought was possible.

"The Taliban frontlines had taken a 'terrible pounding'. The opposition advance was directly the result of an extraordinarily successful bombing campaign helped and coordinated by the people I've seen here today."

The Defence Secretary was speaking during a visit to the armed forces' permanent joint headquarters at Northwood, Middlesex, from where Operation Veritas, the British contribution to the war in Afghanistan is being run.

Mr Hoon was briefed on the progress of the operation by Lt-Gen John Reith, Chief of Joint Operations, who is in charge of all British military operations abroad, and by Commander Paul Chivers RN, the team leader on the Afghanistan desk in the operations control room.

Apart from the role of the SAS on the ground, the British contribution has been the firing of Tomahawk cruise missiles by Royal Navy submarines on two separate days and about 130 missions flown in support of the US bombing campaign by RAF reconnaissance and tanker aircraft. The Defence Secretary said that it was still too early to say what part, if any, British troops might play in the humanitarian aid effort.

The effort is expected to be moved in from Uzbekistan via the newly-captured city of Mazar-i-Sharif. "We're working hard at looking how that can be achieved," said Mr Hoon. "A great deal of work is going on and I am confident, should it be necessary and appropriate, that we have the people who can do the job," he added.