The US commander in Afghanistan today gave his full backing to attempts to reintegrate Taleban members into the rest of the population.

General Stanley McChrystal said that 50 to 80 per cent of the Taleban would probably stop fighting if they were given jobs and he called for “patience, resolve and time”.

The general is known to have asked for up to 40,000 more troops as part of his recent strategic assessment of the mission.

He said that the campaign had been under-resourced in the past to meet the objectives set by the international community. He added that the coalition of 42 nations serving in Afghanistan had “under-performed” in some areas.

“The situation is serious and I choose that word very, very carefully,” he said, speaking at the London-based International Institute for Strategic Studies. “Neither success nor failure in our endeavour in support of the Afghan people and government can be taken for granted.”

General McChrystal made it clear that only the Afghans themselves would be able to say if and when the coalition had succeeded in its mission. To reach that stage, Nato’s International Security Assistance Force (Isaf), which he commands, had to demonstrate that it would support and protect the Afghan people.

“We must respect the people, because ultimately the Afghans must defeat the insurgency,” he said. “In the end we don’t win by defeating the Taleban or by a body count, but when the Afghans have decided that we have won."

General McChrystal flew to London after taking part in a tele-conference with President Obama in the White House. Mr Obama and his closest advisers are reviewing the general’s assessment of what is needed to overcome the Taleban and bring stability to Afghanistan.

He declined to give any details of the discussion but said that he welcomed the debate in Washington and elsewhere. He said that it was important to get the strategy right before investing more resources.

“I think that if we align our goals and resources, we will not have a significant problem. The problem will be if we don’t,” he said.

Despite a relatively gloomy portrayal of achievements so far, he gave reassurance that success was still possible. He acknowledged, though, that one of the reasons why the coalition had not yet succeeded after eight years was that the insurgency had grown despite the influx of troops into Afghanistan. “It took us longer than I wish it had to recognise this is a serious insurgency,” he said.

His determination to turn the campaign round gained support in the audience. Flight Lieutenant Victoria Anderton stood up during questions after his speech and said: “I’m actually going out to Kandahar to serve with the Tornado GR4s next year and can I say how much more confidence I have now in my chain of command than I had after Prime Minister Gordon Brown was here a couple of weeks ago.” Mr Brown addressed the IISS on Afghanistan on September 4 when he defended the war.

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