Bernard Jenkin believes expectations for the ISAF may be too high

Since January they have been helping maintain security in Kabul during the six-month term of the interim administration led by Hamid Karzai.

The UK had previously insisted that its 1,500 troops would be out of Afghanistan by 30 April with Turkey taking over the leading role in the International Security Assistance Force (ISAF) after their withdrawal.

But last week Tony Blair said that negotiations for the handover were still ongoing.

The prime minister's comments came as the Conservatives suggested Britain had put troops into the Afghan peacekeeping mission without knowing how to get them out.

Shadow defence secretary Bernard Jenkin said he believed other countries were reluctant to take over the helm and plans to hand over leadership of the force to Turkey looked in jeopardy.

"Turkey is probably also concerned about where this peacekeeping force is going and has therefore not made a commitment," he said.

Geoff Hoon says British forces will stay until June

"The secretary of state has now written to me to say they have only made an expression of interest."

The Tory spokesman said there was a danger of expectations for the peacekeeping force being too high, both in Afghanistan and in the UK.

But Defence Secretary Geoff Hoon said the terms of Britain's involvement had not changed and the current United Nations mandate for the force lasted until June.

"I indicated when we sent British troops to Afghanistan that our leadership role would remain until the end of April.

"We are still in discussions with other countries, including Turkey, about their likely taking over of that responsibility but it is a considerable responsibility.

"Equally, we always maintained that British forces would remain in Afghanistan until the end of the United Nations security mandate."