Brig Carleton-Smith said the war in Afghanistan cannot be won
The UK's commander in Helmand has said Britain should not expect a "decisive military victory" in Afghanistan.
Brig Mark Carleton-Smith told the Sunday Times the aim of the mission was to ensure the Afghan army was able to manage the country on its own.
He said this could involve discussing security with the Taleban.
When international troops eventually leave Afghanistan, there may still be a "low but steady" level of rural insurgency, he conceded.
He said it was unrealistic to expect that multinational forces would be able to wipe out armed bands of insurgents in the country.
The BBC's Martin Patience in Kabul says Brig Carleton-Smith's comments echo a view commonly-held, if rarely aired, by British military and diplomatic officials in Afghanistan.
Many believe certain legitimate elements of the Taleban represent the positions of the Afghan people and so should be a part of the country's future, says our correspondent.
'Taken the sting out'
Brig Carleton-Smith is the Commander of 16 Air Assault Brigade which has just completed its second tour of Afghanistan.
He paid tribute to his forces and told the newspaper they had "taken the sting out of the Taleban for 2008".
But he stated: "We're not going to win this war.
"It's about reducing it to a manageable level of insurgency that's not a strategic threat and can be managed by the Afghan army."
Brig Carleton-Smith said the goal was to change how debates were resolved in the country so that violence was not the first option considered.
He said: "If the Taleban were prepared to sit on the other side of the table and talk about a political settlement, then that's precisely the sort of progress that concludes insurgencies like this.
"That shouldn't make people uncomfortable."
Since the start of operations in Afghanistan in 2001, 120 UK military personnel have been killed.