By Paul Reynolds
World Affairs correspondent, BBC News website
A leaked British Defence Ministry memorandum has confirmed that London and Washington hope to reduce troop strengths in Iraq next year - but also reveals some of the problems.
Brits in Basra: to be reduced?
The memo does not indicate that basic policy has changed or will change. This is that the troops will be there "as long as is needed".
But the plan is that not so many will be needed.
The authenticity of the memo has been confirmed by the British Defence Secretary John Reid, who signed it.
He has called it an "scenarios" document, but it was prepared for the cabinet committee on defence and foreign policy and it demonstrates how seriously the British government is considering how to reduce its commitment.
These are the hopes:
British troops could be reduced from 8,500 now to 3,000 by the middle of next year.
US troops could be cut from 176,000 to 60,000.
These are the problems:
Everything depends on handing over security to Iraqi control. This in turn depends on the build-up, training and ability of Iraqi security forces.
A handover should happen in two British-controlled provinces, Muthanna and Maysan, in October and the two others, Dhi Qar and Basra, in April 2006.
In the far more dangerous US sector, where most of the fighting is taking place, there are also plans to place security in Iraqi hands in most of the provinces next year.
However - and it is a big however, especially in the US sector - the memo indicates strong disagreements within military staffs about the wisdom of this planning.
The Pentagon and the US Central Command are said to favour large cuts, while local American commanders are more doubtful. These on-the-ground officers feel it is too soon to think about such reductions.
Three factors appear to be putting pressure on the two governments to cut the troop numbers - politics, cost and manpower.
The politics require that Iraq be controlled by Iraqis as soon as possible. This has always been the intention if not the current reality. A reduction would also help both Mr Bush and Mr Blair domestically. But full withdrawal, as carried out by Spain and hoped for by Italy, is not on the horizon.
The memo puts the British government's cost of the Iraqi operation at £1bn a year, and a force reduction to 3,000 would save £500m.
A reduced Iraq commitment would help the UK to find 3,000 more troops for Afghanistan next year. They are needed both to man the Allied Rapid Reaction Corps HQ, which is to be deployed there under British leadership, and to add troops to the fight against the Taleban and the heroin trade.
The US is already having trouble among its reservists and National Guard men and women about service in Iraq, so reduced numbers would help ease retention and recruitment.
There are those who see risks in the plan.
Juan Cole, professor of history at the University of Michigan, who has constantly been a pessimistic voice on Iraq, suggests that this will all threaten the unitary state of Iraq, which can be divided into the Kurdish north, Shia south and the ethnically mixed centre of the country.
"I remain unconvinced that the new Iraqi army will actually be able to take up the slack.
"In practice, I think the withdrawal plan implies a willingness to turn the five northern provinces over to the Kurdish peshmerga paramilitary, and the nine southern provinces over to a combination of Shia militias and new Iraqi government security forces (Interior Ministry gendarmes and regular army). And I think this obviously desperate plan really risks damaging the integrity of Iraq as a nation-state."
Against that, the plan is in line with the goal of the Iraqi, US and UK governments of having elections in Iraq in December on the basis of a new constitution so that a new Iraqi government will be in place by the end of the year and able in due course to control the insurgency and decide the destiny of the country.