Yielding to American pressure, Tony Blair will announce this week that a reduction of British troop levels in Iraq is to be delayed.
Military chiefs have been pushing for an early "drawdown" of forces in Iraq, amid complaints that the armed forces are becoming overstretched by increasing commitments, especially in Afghanistan. Plans had been drawn up to cut the number of bases in south-eastern Iraq and to reduce the British contingent by about 3,000 by the end of the year, from the present level of around 7,100.
But a senior defence source said the Prime Minister would announce a slowdown in the planning: the reduction of about 1,000 troops planned for April will be postponed to August.
Last month the Foreign Secretary, Margaret Beckett, said that Britain would be in a position to hand over security in Basra to the Iraqis "at some point this spring". It is clear that this decision has now been put off until the autumn at the earliest.
American disquiet has been evident for some time. Apart from political concern in Washington at the perceived loss of support from its principal ally in Iraq, it emerged last month that US commanders were pressing Britain to keep open Shaibah logistics base, in the desert south of Basra. Until this year Shaibah was the largest British base in Iraq, but its closure was considered imminent as personnel and resources were switched to Basra air station, now the main centre of operations. The Americans, however, fear that the strategic supply route from Kuwait could become vulnerable.
Mr Blair is expected to announce this week that any handover of Basra air station, on the outskirts of the city, and Basra Palace - built for Saddam Hussein on the banks of the Shatt al-Arab, and housing UN, American and British consular staff - to Iraqi control will also be delayed.
The news will be a blow to military chiefs, whose impatience to wind down the mission became public last October. The head of the Army, General Richard Dannatt, said the presence of British forces in Iraq was exacerbating the security situation, and they should "get out some time soon".
Meanwhile Lord Goldsmith, the Attorney General, faces pressure to explain why an army colonel was charged with war crimes, after Colonel Jorge Mendonca was cleared last week of abusing Iraqi civilian prisoners. Col Mendonca walked free after a judge ruled that he and three of his men had no case to answer.
Lindsay Hoyle, the Labour MP whose Chorley constituency includes much of the regiment's recruiting area, said that Lord Goldsmith was "determined to go ahead" with the court martial, despite widespread doubts that it would lead to a conviction.
A spokesman for the Attorney General said that the decision to prosecute Col Mendonca and his co-defendants was made by the army prosecution authority. "There is no question of the prosecution having been politically motivated or influenced by political pressure," he added.