David Cameron has said he hoped some British forces could start pulling out of Afghanistan as early as next year.
The Prime Minister raised the prospect of a limited withdrawal in 2011 after talks with US president Barack Obama.
A major conference in Kabul on Tuesday backed a plan that would see responsibility for security in some areas begin to be handed over to Afghan forces later this year with an aim of full handover by 2014.
Mr Obama has said he plans to reduce US troop numbers from July next year.
Asked if the UK could do the same the PM told BBC Radio 5 Live: "Yes, we can but it should be based on the conditions on the ground. I mean, the faster we can transition districts and provinces to Afghan control, clearly the faster that some forces can be brought home. I don't want to raise expectations about that because that transition should be based on how well the security situation is progressing.
"People in Britain should understand we're not going to be there in five years' time, in 2015, with combat troops or large numbers because I think it's important to give people an end date by which we won't be continuing in that way.
"But I hope that with the strategy we have, the build-up of the Afghan army, the transitioning of districts of provinces, as the president said, it will be possible to bring some troops home."