I’m pretty sure that one of the conditions for the Liberal Democrats to enter into a coalition with the Tories was that a hard date be set for a withdrawal from Afghanistan, and the recent statement by the Defens(c)e Minister would appear to confirm this:

Senior British officials, including new Foreign Secretary William Hague arrived in Afghanistan May 22 with a warning that Britain wants to withdraw its troops as soon as possible.

Hague, Defence Secretary Liam Fox and International Development Secretary Andrew Mitchell are set to meet President Hamid Karzai in their first visit to the country since a new coalition government took power in London this month.

…………

In an interview with The Times newspaper before arriving in Kabul, Fox made clear the visit would focus on speeding up the withdrawal of British troops from Afghanistan, and that no new troops would be deployed.

“We need to accept we are at the limit of numbers now and I would like the forces to come back as soon as possible,” he was quoted as saying.

“We have to reset expectations and timelines.

“National security is the focus now. We are not a global policeman. We are not in Afghanistan for the sake of the education policy in a broken 13th-century country. We are there so the people of Britain and our global interests are not threatened,” Fox said.

Another contributing factor is that the Afghanistan adventure is phenomenally unpopular in Britain, so a continued trip down the path in the Hindu Kush is politically suicidal, notwithstanding any “special relationship”.