By Nick Assinder
Political correspondent, BBC News website
Tony Blair has lost no time in signalling that President Bush's plans for a troop "surge" in Iraq will have no effect on British moves to gradually reduce force numbers in the country.
Blair and Bush have different troop plans
Indeed, all the talk in Westminster now is around speculation that the draw down of up to 3,000 UK troops may be under way by May - in the weeks leading up to the prime minister's expected retirement day.
The aim of these two developments is to seek to reassure voters that, whatever the US does, it will not lead to an increase in British involvement in the country or blow the government's plans off course.
Ministers are eager to point out, as Mr Blair reminded the Cabinet on Thursday morning, that conditions on the ground in the UK's zone of operation in Basra are entirely different from those in Baghdad, which is the focus of the US movement.
Specifically, they point to the success of operation Sinbad - which is purging the police of the militias that have infiltrated their ranks - and the rebuilding of the region's infrastructure.
Ministers hesitate to be specific, but it is believed the handover of responsibility for the area to local officials may look realistic later in the spring.
But many are already asking whether the UK will be able to insulate itself from the actions being taken by President Bush or whether things will actually take a turn for the worse as a result of the "surge".
Liberal Democrat leader Sir Menzies Campbell voiced that concern during prime minister's questions on Wednesday.
US troop numbers will increase substantially
The assumption that the US deployment would not lead to a "displacement of terrorist activity from Baghdad to Basra" was difficult to make, he declared.
And that must be a real danger for the prime minister, who will be desperate not to see any worsening of the situation in Iraq in the last months before his resignation.
Worse, there is the danger that any knock-on effect from the president's decision - itself being seen as high-risk - will underpin the view already held by many that events are out of Mr Blair's hands.
Those critics have long argued that UK policy has been determined by the White House, with Mr Blair having no option but follow the Mr Bush's lead.
That impression has been heightened by suggestions the president's decision was taken with little or no consultation with the prime minister.
Mr Blair's official spokesman flatly denies that, insisting there has always been close coordination between the prime minister and the president and that both the US and UK strategies are "symmetrical".
The aim for both countries is to create the conditions in which the Iraqi authorities can take responsibility for their own security and economy.
But it is also being pointed out that the president has ignored the Iraq Study Group's key recommendations for constructive engagement with Iran and Syria - something Tony Blair has also been pressing for.
If the new deployment actually increases attacks on UK forces or even leads to suggestions more British troops might be needed, it would prove damaging for Mr Blair.
Yet, if the UK drawdown continues as planned while the US boosts its presence, that might please those who have been looking for a different approach from Mr Blair.
The prime minister's task in the meantime is to continue to persuade voters that there really is the claimed "symmetry" of approach between him and George Bush.