British troops will start pulling out of Iraq in March and, by next summer, there will be just 400 British personnel in the country, a senior defence source said yesterday.

The troops will make way for several thousand American soldiers who are to move into the British base at Basra airport, in the south of the country. The SAS squadrons that are currently operating from Baghdad on counter-terrorist missions will also be withdrawn and are expected to be transferred to Afghanistan to fight the Taleban.

The precise timing of the first homecomings will depend on the arrival of an American two-star military headquarters, which will be set up at the airport base northwest of Basra city.

Plans are now well advanced for the withdrawal of Britain's 4,100 troops even though a “status of forces” agreement has yet to be reached with the Iraqi Government.

In March a few units will withdraw, marking the beginning of the end of the British campaign, codenamed Operation Telic. The speed of withdrawal will quicken as the US troops begin to deploy in southern Iraq.

A brigade of between 4,000 and 5,000 US troops is expected to set up home at the airport, which has been the principle location for Britain's military presence in Iraq over the past five years.

The US forces will extend their reach south of Baghdad, partly in order to guard supply routes from Kuwait. The British job of “mentoring” the Iraq Army's 14th Division in Basra is expected to be completed within three months.

Under present planning, the reduced British force of about 400 will include the Service personnel who are based in Baghdad, with the exception of the SAS squadrons. Some British personnel will remain in the south to continue training the Iraqi Navy at Umm Qasr port, after a specific request for them to do so by the Baghdad Government.

The Iraq withdrawal programme is still dependent on security conditions in southern Iraq, and there will be some anxiety about possible violence during the provincial elections that are due to be held on January 31.

However, British commanders believe that the Iran-backed Shia extremists who led attacks against British troops until earlier this year are unlikely to return to renew their insurgency. Many of them are believed to have gone to Iran. Iraqi commanders now in charge of security in Basra have vowed to deal harshly with any extremists who try to return to the city.

Underlining British confidence that the Iraqi Army and police in Basra will be able to cope on their own, the defence source said it was unlikely that the next Iraq-bound brigade, which is currently training for deployment in the spring, would ever be sent.

Troops of 12 Mechanised Brigade are set to replace 20 Brigade but, although their training will continue, they will eventually be told to stand down. No pledges have been made by the British Government to send reinforcements to Afghanistan once the pullout in Iraq has taken place. However, ministers are considering the option of deploying more troops to Afghanistan for a limited period to provide extra security for next year's presidential election.

Under the Iraq withdrawal programme, codenamed Operation Archive, all the equipment, including the vast tented accommodation complex at the Basra airport site, will be packed up and shipped back to Britain. “The tents will be put on the shelf for another occasion,” the source said.

Some of the most valuable equipment, however, will be transferred to Afghanistan. This will include the half-dozen Merlin helicopters that are operating in Iraq and all the pilotless Desert Hawk drones.

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