Thousands of American troops are being poured into southern Afghanistan to break the "stalemate" in the region, the senior British commander in the country said today.
General Jim Dutton, deputy commander of Nato forces in Afghanistan, denied that the British forces based in Helmand province in the south had been fighting a "losing campaign" against the Taliban.
But he acknowledged that "neither side could progress much" with the present force levels.
"In order to break that stalemate, to increase the capacity, the decision was made to bring many more forces into the south," he said in an interview with the BBC.
His acknowledgement that US reinforcements were needed to defeat the Taliban is likely to lead to further criticism that the Government failed to commit sufficient forces to the campaign.
The Government recently ruled out any permanent increase to the 8,100-strong British contingent in the country, despite reports that service chiefs had been pressing for 2,000 additional troops.
In contrast, many of the additional 21,000 US troops being deployed by President Barack Obama are being sent to Helmand in an effort to force a strategic breakthrough against the Taliban.
Gen Dutton welcomed their arrival but said it will take until the autumn or winter of this year before the full impact of the reinforcements is felt.
"I am convinced that the addition of those troops is going to improve the security situation," he said.
Another reason for optimism, he said, was the realisation that Pakistan is just as important to the war effort as Afghanistan.
The border between the two countries is now "much better controlled" and the situation will continue to improve.
"I'm not saying we're now in a position where we wholly control the border and the border has become irrelevant - far from it. But we are in a much better position in that respect than we have been in the past," he said.
Gen Dutton said commanders were taking further steps to try to prevent civilian casualties, which have become a major cause for concern within Afghanistan.
"Things are still going to go wrong, but the fundamental mindset change that has been taking place for some time is ... if you are in a situation where there is any chance of creating civilian casualties, or you don't know whether you will create civilian casualties, if you can withdraw from that situation without firing then you must do so," he said.