“There's always been a point at which you start to negotiate with each other," Gen Sir David said. In his “private view” there was “no reason why we shouldn't be looking at that sort of thing pretty soon,” he said.
It was the 19th British fatality this month, raising the total close to last June’s record of 22. In all 308 British servicemen have now died in the Afghan campaign.
Another allied soldier was killed yesterday, bringing Nato’s death toll to 91 this month, which was already the deadliest for international forces since the war began in 2001.
Liam Fox, the Defence Secretary, will this week warn the public to brace itself for a summer of “increased casualties” as troops engage in more intense fighting.
About 10,000 British soldiers are fighting in Afghanistan. Many are engaged in a counter-insurgency campaign in Helmand province in the south of the country.
Gen Sir Richard Dannatt, Gen Sir David’s predecessor, told the BBC yesterday that the military must continue to put “maximum pressure” on the Taliban and have the “strategic patience” to clear them out of Afghanistan.
He urged ministers to provide an urgent boost in funding for troops on the ground, at the expense of future projects. “The here and now is staring us in the face,” he said.
He appeared to play down David Cameron’s suggestion that troops should leave in less than five years. He said the Taliban should not be given a timetable to "sit this out for five years, 10 years or whatever".
Yet Gen Sir David later said that while fighting must continue “to make sure that they don't think that we are giving up”, allied politicians and military chiefs should begin talking to the Taliban sooner rather than later.
He told BBC Radio 4 that he was sceptical a complete military defeat could ever be inflicted on the Taliban, however many smaller victories were won by British troops.
"I think on one level, the tactical level, the lower military level, we need to continue to make the Taliban feel that they are being punished for what they are doing in a military sense,” he said.
"So that needs to continue, but whether we can turn that into some sense of strategic defeat I'm less certain."
Dr Fox will this week address American politicians and military chiefs during his first official ministerial visit to Washington.
He will seek to reassure them that Britain will continue to stand “shoulder to shoulder” with the United States, but will be clear that more soldiers will die.
“Political and military leaders need to brace the public for a summer of intense fighting and increased casualties,” Dr Fox is expected to say.
Sources close to Dr Fox suggested that, like Gen Sir Richard, he would stress that Britain will have the “strategic patience” to complete the mission and not seek a “calendar-based withdrawal”.
However Nick Harvey, Dr Fox’s Lib Dem armed forces minister, warned yesterday that public support for British troops had suffered “huge damage” because of the Iraq war.
Mr Harvey said the “questionable legality and morality” of the Iraq invasion had seriously harmed the public's view of the longer mission in Afghanistan.
“It is a difficult message to get across,” he said at a memorial service in Plymouth. “We would be much further on in Afghanistan now if we had not diverted attention off to Iraq in 2003."
