Britain's military force in Afghanistan could be almost halved during 2013 under options to be discussed by David Cameron and security chiefs next week, it was reported.
The Prime Minister will chair a meeting of the National Security Council on Tuesday which will consider the strategy for withdrawal - due to be complete by the end of 2014.
One of the options on the table, the Guardian said, was to pull out 4,000 of the 9,000-strong contingent during 2013 and a similar number the following year.
The newspaper said the accelerated withdrawal had the backing of at least two senior Cabinet ministers, in a bid to cut the costs of the decade-long campaign.
It would be at odds, however, with the desire of Nato commanders who are pushing for significant reductions to be delayed until 2014.
A middle option to be considered by the NSC would involve 2,500 troops leaving during 2013, the Guardian said.
In the summer, Mr Cameron announced the drawdown of a further 500 troops, cutting total force numbers to 9,000 by September 2012.
He has repeatedly declared that there will be no British troops engaged in major combat operations after 2014 - the deadline for handover to Afghan security forces.
The Commons Defence Select Committee has warned against any premature withdrawal of British troops, arguing that it could undermine the international coalition's strategy while dangerously weakening the remaining forces.
A Government spokesman said: "The NSC discussions will take place within the context of the wider international effort. As the Foreign Secretary set out in Bonn this week, the international community will continue to support Afghanistan long after 2014 to help build national safety, security and prosperity."