Royal Marines of 40 Commando are being withdrawn from Kabul as the drive to stabilise and re-integrate Afghanistan into the world community gathers speed.

In a statement to the House of Commons yesterday, Defence Secretary Geoff Hoon spoke of the rapid progress that had been made in the establishment of an International Security Assistance Force (ISAF), which is already patrolling the streets of the Afghan capital.

As lead nation, the UK has been responsible for assembling the force, which he emphasised is there at the invitation of the Afghan Interim Administration under the auspices of a Military Technical Agreement signed on January 4.

Under the terms of the agreement, the ISAF will operate only in Kabul., and British troops have now been on patrol for a fortnight, while French colleagues joined them yesterday. Mr Hoon added that "these patrols have been extremely well received by the people of Kabul."

At a planning conference just before Christmas, 21 nations offered forces for ISAF, many of the offers being of infantry - but the particular requirements of the job meant specialist elements needed to be included.

"We had to construct a balanced and capable force able to get to Afghanistan quickly, support itself, and do its job," said Mr Hoon.

"The ISAF needs logistics support. It needs Explosive Ordnance Disposal troops. It needs signallers. It needs engineers. It needs medical units. It needs helicopters. And, given that it will deploy and be supplied by air, it needs air transport."

Mr Hoon said he expected the force to be around 5,000 strong, with 18 countries contributing in total - the UK, Austria, Belgium, Bulgaria, Denmark, Finland, France, Germany, Greece, Italy, the Netherlands, New Zealand, Norway, Portugal, Romania, Spain, Sweden and Turkey.

The nature of the countries' involvement varies - the Austrians, Danes and Dutch are deploying forces as part of a German-led multinational infantry battlegroup, New Zealand and Turkey are providing HQ staff and support troops, Norway is providing bomb disposal teams and Romania has offered air transport and military police.

Mr Hoon said the UK will lead the force for three months only, and the country's total contribution will be around 1,800 strong. In addition, a short-term deployment of 300 Army and RAF personnel will help repair and operate Kabul International Airport., which will help resupply the ISAF.

Turkey has already expressed an interest in taking over from Britain in three months time, when "we would expect to see a significant reduction in the number of British troops deployed," said Mr Hoon. The ISAF is expected to reach peak strength next month.

"We are now withdrawing the elements of 40 Commando Royal Marines who have helped secure Bagram Airstrip," Mr Hoon added.

But the Navy still has a job to do.

"The Royal Air Force is still flying reconnaissance and air-to-air refuelling sorties," said Mr Hoon.

"The Royal Navy is playing an important role in the coalition maritime force in the region, and is patrolling in the Arabian Sea to prevent those with links to the Al Qaeda network escaping from the region. I pay tribute to the work they are doing."

Mr Hoon also referred to the humanitarian mission which has been stepped up - the World Food Programme sent 116,000 metric tonnes of wheat to Afghanistan in December, against a target of 100,000 tonnes, the highest monthly distribution figure to date.