The public should not expect "a decisive military victory" in Afghanistan, Britain's most senior military commander in the country warned.
Brigadier Mark Carleton-Smith said the aim was to reduce the uprising to a level at which it could be managed by the Afghan army and made clear that this could involve talking to the Taliban.
It was necessary to "lower our expectations" and accept that it would be unrealistic to expect that multinational forces can entirely rid Afghanistan of armed bands, he suggested.
Brig Carleton-Smith, the commander of 16 Air Assault Brigade, which has just completed its second tour of Afghanistan, told the Sunday Times that his forces had "taken the sting out of the Taliban for 2008".
But he added: "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.
"We may well leave with there still being a low but steady ebb of rural insurgency."
Talks with the Taliban about a political settlement should not be ruled out, he added.
Brig Carleton-Smith said the aim should be to change the nature of the debate in Afghanistan so that disputes were settled by negotiation and not violence.
"If the Taliban 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," he said.
"That shouldn't make people uncomfortable."