British troops were being stood-down from their 48-hour mobilisation standby last night as the deployment of 1,000 American Marines signalled a new phase of the war in Afghanistan.
The Defence Secretary, Mr Geoff Hoon, told MPs some soldiers - from 2 Battalion Parachute Regiment and 16 Air Assault Brigade - would remain on two-day standby, but that the "bulk" of the 6,000 originally placed on 48-hour alert following the fall of Kabul were having their "notice to move" extended to one week.
Mr Hoon said the changing situation in Afghanistan had made possible this move as "a measured response" while allowing the UK "maximum flexibility" to react to new developments.
A spokesman for the prime minister echoed this assessment, saying Mr Hoon's announcement was "a direct result of the situation being better than anyone could have predicted, rather than worse."
And he insisted Britain would continue to play a significant military role in Afghanistan with troops "ready and willing" to be deployed .
Mr Hoon used his appearance before MPs in the Commons to again deny reports of a transatlantic rift over the issue of troop deployment.
Asked on BBC Radio 4's PM programme whether British troops would be involved in the US effort around the Taleban stronghold of Kandahar, Mr Hoon said there was British co-operation with the US "right across the field of operations in Afghanistan".
Mr Hoon also reported the first British casualties in Afghanistan resulting from those joint operations.
He told MPs that four service personnel had been injured in the region and were already back in Britain being treated for their injuries, which were not believed to be life-threatening.
No details were forthcoming about the specific operation in which the casualties occurred.
However, it is understood that the four might be special forces deployed alongside the Americans in the region, and that they were not attached to the Royal Marine Commando deployed at the Bagram airbase, near Kabul.
Mr Hoon confirmed yesterday that that deployment had been "augmented" over the weekend.
The Defence Secretary paid tribute to the "professionalism and gallantry" of UK soldiers as he gave news of the injuries.
He said British forces had been "active on the ground inside Afghanistan for some time" and engaged in a range of operational tasks in different parts of the country.
The four service personnel had been injured at the same location during the past few days, he said.
Their relatives had been informed.