The head of the British Army has put a question mark over the 2015 deadline for troops withdrawing from Afghanistan.
Prime Minister David Cameron has said the deadline is definite and that a "clear end point" is needed.
But although General Sir Peter Wall stressed that the Army is "committed to deliver against that deadline" he added that "whether or not it turns out to be an absolute timeline or more conditions-based approach nearer the time, we shall find out".
He was interviewed for a BBC Two documentary, titled Afghanistan: War without end?", in which the Prime Minister also discussed the 2015 deadline.
Mr Cameron, asked if he would still withdraw troops whether or not the state of Afghanistan was capable of resisting the Taliban, replied: "No. The deadline is a deadline, and it won't slip because I'm very clear that the British people deserve to have a clear end point."
The US government has said its troops will only be withdrawn when the Afghans "are ready" to resist the return of the Taliban who reportedly gave al-Qaeda a base while they were governing the country.
General Wall is asked if he accepts that many of the "hearts and minds" of Afghan civilians have in fact been lost, instead of won over by the Army. He replied: "Undoubtedly. Yeah, undoubtedly. I accept that."
He said he did not believe the Helmand mission had changed from the reconstruction plan set out by then defence secretary John Reid. He added that if troops had not deployed to the north of the country, then "Afghan governance in Helmand would have collapsed, I think".
The documentary also reveals that the Taliban had already agreed terms of surrender with Hamid Karzai, the current president of Afghanistan, before their eventual surrender in December 2001.
Taliban spokesman Abdul Hakim Mujahid said Karzai had agreed that their soldiers could go home. However, the Bush administration rejected the deal.