US withdrawal set to leave British exposed

British forces in southern Afghanistan risk bearing the brunt of America's drawdown - unless the current campaign plan is drastically rewritten - because most of the soldiers President Barack Obama ordered home are based in Helmand and neighbouring Kandahar, alongside UK troops.

Nato officials said the decision to cut 10,000 American troops by the end of this year and a further 23,000 by September 2012 has left commanders in Kabul frantically trying to work out how they can plug the gaps without losing what they insist are "fragile and reversible gains".

Overstretched British troops, who once spanned the length of Helmand, were the prime beneficiaries of Mr Obama's "surge", because the incoming US Marines took control of volatile and far-flung towns - including Sangin, Musa Qala, Now Zad, Kajaki and Garmsir - so the British could focus on a much smaller area in the centre of the province, close to the capital Lashkar Gah.

Although officials said it would be "unthinkable" for British troops to reoccupy old bases, UK troops are likely to make up a much larger proportion of the foreign forces, who do the bulk of the fighting, once the draw-down is complete next year.

Lieutenant-General David Barno, US commander in Afghanistan between 2003 and 2005, said the first soldiers to leave would not necessarily come from Helmand or Kandahar, because they are still mid-way through their 12-month tours.

He said commanders would try to pick units in more stable areas, in the north and west, to send home first.

However, officials in Kabul said it would be "all but impossible" to maintain the current troop density once there were 33,000 fewer soldiers.

Canada has already said it will end combat operations this year and France announced yesterday that it would start withdrawing 1,700 of its 4,000 troops.

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"Ultimately, the marines in Helmand will have to go home," said a Nato official.

"They will probably back fill them with US troops from somewhere else in Afghanistan, but there aren't many places to chose from, there will be fewer soldiers and lots of places still need extras."

The impact on British troops could be compounded this autumn, the official said, if commanders press ahead with existing plans to redeploy frontline troops from the south to the east, where violence has soared in recent months.

"Once the safe-havens and strongholds in Helmand had been cleared, the idea was to move some of those soldiers to the east, to help there," he said.

Although violence has trailed off in Helmand over the past three months, independent figures show attacks are still more frequent than in the same period in 2010.

General David Petraeus, the outgoing commander of Nato forces in Afghanistan, said yesterday he had recommended a slower drawdown than Mr Obama had decided upon, but backed the decision and said no military commander in history gets "all the forces he would like to have, for all the time".

"The ultimate decision was a more aggressive formulation, if you will, in terms of the timeline than what we had recommended," Gen Petraeus told a Senate hearing on his nomination to become CIA director.

"Again, that is understandable in the sense that there are broader considerations beyond just those of a military commander."

US defence secretary Robert Gates admitted he had "preferred options that gave more time".

Admiral Mike Mullen, Chairman of the Joint Chiefs of Staff, endorsed Mr Obama's decision, but conceded it was "risky".

"No commander ever wants to sacrifice fighting power in the middle of a war," he said. "And no decision to demand that sacrifice is without risk."

However, the announcement was welcomed inside Afghanistan. President Hamid Karzai called it a "joyous occasion" and claimed it was proof that "Afghans are capable of securing their own country". In a statement that echoed earlier accusations that America was behaving like an occupying force, he said: "Our 5,000-year history and our 30 years of experience show that this land can only be kept by Afghans."

Dr Abdullah Abdullah, Mr Karzai's main political opponent, also said he welcomed the principle of transition to Afghan control.

In a bid to rally morale, Gen Petraeus told his staff that 100,000 Afghan soldiers had been trained since the surge began, and another 70,000 would be in uniform before the drawdown was over.

But analysts are skeptical of the Afghan army's ability. In Nuristan province, one of the places where US forces have already withdrawn, the Taleban overran Afghan garrisons left behind and retook control of the area.