David Cameron has demanded British troops are withdrawn from Afghanistan.

But his words have sparked a row with military leaders who believe soldiers are still needed in the country.

In a bid to bring the ten-year mission to an end, the Prime Minister has told the Army that soldiers should be brought back from the war zone within weeks.

But his plan - in response to the news of Osama Bin Laden's death - has been fiercely opposed within Whitehall, it was reported today.

Defence chiefs have drawn up plans to remove 450 troops from Britain's total of 10,000 in a compromise deal with Downing Street, but none are thought to be combat soldiers.

Those in charge fear the counter-insurgency mission against the Taliban would be harmed by early troop withdrawals.

A Whitehall source told The Daily Telegraph: 'There is a very active conversation going on. On one side there is the military concern about force density and continuing the mission, and on the other side the PM's political imperative for some sort of announcement on draw-down.'

The combat mission is due to end completely in 2014, but the death of Osama Bin Laden had speeded up the need for withdrawal in the Prime Minister's eyes, it is claimed.

A total of 364 British troops have died in Afghanistan since 2001.

 All British troops will leave Afghanistan by 2014

Mr Cameron's intervention came as the head of the Royal Navy warned the service would struggle to build up a force of fighter jets to equip its planned new aircraft carrier.

Admiral Sir Mark Stanhope, the First Sea Lord, told MPs he wished he could revisit the Government's decision to axe HMS Ark Royal and its Harrier jets, leaving the UK without a carrier for the rest of the decade.


Admiral Stanhope has warned the decision to scrap the Ark Royal may limit the Navy's capability

Giving evidence to the Commons Defence Committee, he said that if the Navy still had a carrier it would be deployed on the current international operations in Libya.

'If we had a carrier it would be there,' he said.

The committee also heard from the head of the Army, General Sir Peter Wall, and the head of the RAF, Air Chief Marshal Sir Stephen Dalton, who both said their services were 'running hot' as a result of conducting simultaneous operations in Libya and Afghanistan.

Admiral Stanhope said the decision in the Strategic Defence and Security Review to scrap Ark Royal before the new carrier joins the fleet in 2020 could limit Britain's ability to provide air support for UK forces around the world.

Although the Government is committed to building the two carriers ordered by the former Labour government - a cancellation was too expensive - only one will actually enter service, with the second due to be mothballed or sold.

However Admiral Stanhope told the committee that could still leave the UK without a carrier capability for around three out of every eight years due to the need for periodic refits.

'I am very clear that if you want a capability that is available to this nation continuously, you can't do that with one carrier,' he said.