LONDON -- Prime Minister Tony Blair is expected to announce Britain's first major troop pullout from Iraq, with 1,500 troops likely to return home within the next few months, British news agencies reported yesterday.
A total of 3,000 troops - more than 40 percent of Britain's contingent in Iraq - could be pulled out by the end of the year, if the handover of security to Iraqi government forces in the southern part of the country continues to go smoothly, the reports said.
Britain has long been the most important coalition member in Iraq after the United States. But Blair knows that the British public and politicians from his own Labor Party want the troops out as quickly as possible and don't want to see Britain stick with the U.S. in Iraq for the long haul.
Militarily, a British withdrawal isn't likely to have much effect on the stepped-up U.S. operation in Baghdad or the war with the Sunnis in Anbar province west of the Iraqi capital. However, Iraqi forces could have a tough time maintaining security in mostly Shiite southern Iraq, including Basra.
The expected announcement to Parliament today, which the prime minister's office declined to confirm, follows the British government's pledge to consider drawing down troops this year as the Iraqi military and police shoulder more responsibility for quelling sectarian violence.
An important signal came earlier this week, when Blair announced that a program to give Iraqi troops "main front-line control" of security in the southern city of Basra had been "successful," clearing the way for British troops to assume a largely supportive role.
Critics have questioned just how successful Iraqi forces have been when taking charge. The Iraqis have also been assigned the lead in at least two other provinces of southern Iraq.
"It is absolutely true, as we have said for months, that as the Iraqis are more capable down in Basra of taking control of their own security, we will scale down," with the proviso that sufficient troops are "in reserve" to help in the event a "particular problem arises," Blair told the BBC's Sunday AM over the weekend.
"The operation that we have been conducting in Basra is now complete, and that operation has specifically been to put the Iraqi forces in the main frontline control of security within the city," he said.
He said British forces in the south face a somewhat easier task than that of the Americans, who are preparing to deploy 21,500 additional troops in Baghdad and Anbar province, because there are no Sunni insurgency or al-Qaida suicide attacks in the predominantly Shiite Basra area.
Several British newspapers and the BBC reported that Blair will tell Parliament today that he plans to reduce Britain's 7,100-troop contingent to 5,500, with most of the reduction coming from troops now deployed in Basra.
A Blair spokesman said last night: "The prime minister has said that Parliament will have to be told about this matter first."
In Washington, the White House said it is grateful for Britain's past and future military support in Iraq. Blair and Bush spoke yesterday, when the British prime minister presumably briefed Bush on his plans.
"While the United Kingdom is maintaining a robust force in southern Iraq, we're pleased that conditions in Basra have improved sufficiently that they are able to transition to more control to the Iraqis," National Security Council spokesman Gordon Johndroe said.
"The United States shares the same goal of turning responsibility over to the Iraqi security forces and reducing the number of American troops in Iraq," he said.
Of Blair's conversation with Bush, he said: "President Bush sees this as a sign of success and what is possible for us, once we help the Iraqis deal with the sectarian violence in Baghdad."
As recently as late last month, Blair rejected opposition calls to withdraw all British troops by October, calling such a plan irresponsible.
"That would send the most disastrous signal to the people that we are fighting in Iraq. It's a policy that, whatever its superficial attractions may be, is actually deeply irresponsible," Blair said Jan. 24 in the Commons.
Blair, who has said he will step down as prime minister by September after a decade in power, has seen his foreign-policy record overshadowed by his role as Bush's leading ally in the unpopular war.
Last month, Blair said he would report to lawmakers on his future strategy in Iraq after the completion of Operation Sinbad, a joint British and Iraqi mission targeting police corruption and militia influence in Basra.
On Sunday, Blair told the BBC that the operation was completed.
Foreign Secretary Margaret Beckett said in January that Operation Sinbad offered the prospect of a "turning point for Iraq, hopefully in the near future."
Treasury chief Gordon Brown, who is likely to succeed Blair, has said he hoped several thousand British soldiers would be withdrawn by December.
Kim Murphy writes for the Los Angeles Times. The Associated Press contributed to this article.