There has been a brilliant victory over Taleban ... but we know that is only the start of enabling Afghanistan to cease being a failed state

Tony Blair

Mr Blair updated MPs on plans for the force as he made a Commons statement on the European Union summit in Laeken, which took place at the weekend.

He repeated that the UK was "willing in principle" to lead the peacekeeping force, which he said would include troops from both Europe and elsewhere.

A meeting of possible troop contributors in London last week included several EU nations, as well as Argentina, Canada, Australia, New Zealand, Jordan, Czech Republic, America, Malaysia and Turkey, said Mr Blair.

Arrangements for the force were not expected to be finalised until the United Nations makes a resolution later this week giving a mandate to the peacekeeping mission.

A senior British Army officer has been in the Afghan capital, Kabul, to liaise with the country's new interim administration on how the force would operate.

Timing

Major General John McColl will report back to ministers before a final decision is taken on its make-up and strength.

Mr Blair said there was no question the full force could be deployed before 22 December when the interim Afghan administration is due to take power, but some of its lead elements could be in place.

Mr Blair has constantly offered British help

The force was a "critical" part of the Bonn agreement which set up that interim administration, Mr Blair continued.

"There has been a brilliant victory over Taleban... and that of course has been a welcome liberation.

"But we know that is only the start of enabling Afghanistan to cease being a failed state and become a responsible partner in the region."

Troops as targets

Doubts were raised over British involvement in the force by Conservative leader Iain Duncan Smith.

The Tory leader voiced his "misgivings", which included fears the British troops could become targets for the remaining Taleban fighters and other opponents to the interim settlement.

That was a particular danger when other UK troops were involved in "search and destroy" missions elsewhere in Afghanistan.

Mr Duncan Smith also pressed for an "exit strategy" for any troop deployment and argued there should be a time limit to the mission.

Liberal Democrat leader Charles Kennedy asked about how robust the rules of engagement would be for British troops.

Mr Blair said the rules had yet to be finalised but everything possible would be done to protect UK soldiers.

The prime minister's official spokesman earlier dismissed reports that the UK could send as many as 6,000 troops.

Limited remit

Alliance Defence Minister General Mohammed Fahim has told the UK-led military team in Kabul that only 1,000 peacekeepers are needed.

He wants them to be limited to providing security for the regime, but some Western nations have argued for as many as 8,000 troops with a wide remit.

The prime minister's spokesman dismissed speculation on numbers and rows in the military about the danger of overstretching the army as "24-carat nonsense".

The spokesman indicated that the length of time that is being taken was an illustration of the government's desire to make the right decision.

European clash

Mr Blair's statement on the Laeken summit also prompted a heated exchange between the prime minister and Mr Duncan Smith over European policy.

The Conservative leader claimed the council was about "greater moves towards a European state".

Mr Duncan Smith particularly attacked plans for a common European defence policy.

Mr Blair hit back, saying: "At some point, hopefully, his party will come back to a realistic sensible position on Europe but until they do frankly there are barely qualified as an opposition, let alone a government."