More British troops will lose their lives as a result of a strategy being brought in to reduce civilian casualties, the new commander of Nato forces in Afghanistan warned yesterday.

General Stanley McChrystal — who has ordered his forces to reduce aerial bombing because of the risk to civilians — said that the additional risks to soldiers were a price worth paying.

If the Afghan people swung behind the Taleban this would ultimately make the war unwinnable, the American commander said. “In the long run it is more economical in terms of loss of life to operate this way because we can gain the support of the population,” he told The Times.

General McChrystal, who took over as commander of the Nato International Security Assistance Force last month, acknowledged that British troops had suffered “painful casualties” recently. Seven British soldiers have died in as many days in Helmand as part of Operation Panther’s Claw.

He criticised Britain’s resourcing, saying that the force sent to southern Afghanistan — 3,300 troops in 2006, rising to 9,000 now — was given “tasks wider than its numbers allowed it to do”. This, he said, had given the Taleban time to “burrow deep” into large areas of Helmand that Nato troops were now fighting to secure. The US has sent 4,000 Marines there as part of its 21,000-troop surge.

The warning of higher casualties came as a member of the Light Dragoons was killed by an explosion near Gereshk, in Helmand. Bob Ainsworth, the Defence Secretary, admitted that the death toll had caused worry but denied that the conflict was becoming another Vietnam. “I don’t accept that — we have made considerable progress,” he said. “More lives will be lost and our resolve is going to be tested. If we are to succeed, we will need both the courage and the patience to see it through. There is no defined end date, only an end state.”

Nick Clegg, the Liberal Democrat leader, writes in The Daily Telegraph today: “Recent events have led me to question whether we’re going about things in the right way. Lives are being thrown away because our politicians won’t get their act together.”

When General McChrystal was asked if he was sacrificing the lives of Nato soldiers to save Afghan civilians, he said: “I believe that risks we accept now save coalition soldiers in the long run. If you create antipathy, you are going to create more insurgents.” A recent poll found that 23 per cent of southern Afghans backed the Taleban.

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