Britain will withdraw all but 400 of its troops from Iraq by the end of next July, Prime Minister Gordon Brown said Thursday, but rejected any link with pressure to send more forces to Afghanistan.
The British premier also rebuffed growing calls for a formal inquiry into Britain's decision to join US President George W Bush in the controversial US-led invasion of Iraq.
Speaking in the House of Commons a day after making a surprise visit to the violence-scarred country, Brown said: "The fundamental change of mission... will take place at the latest by May 31, 2009.
"At that point we will begin a rapid withdrawal of our troops, taking the total from just under 4,100 to under 400 by July 31. The majority of those remaining troops will be dedicated to naval training," he added.
The timetable is in line with a bill approved by the Iraqi cabinet calling for all foreign troops except for US forces to end their missions by the end of May and pull out definitively by the end of July
The deployment of US troops is governed by a landmark security pact.
Most of Britain's remaining troops in Iraq are based near the southern Iraqi city of Basra, which Brown visited on Wednesday after an unannounced trip to Baghdad.
Brown's predecessor Tony Blair was widely criticised for his decision to join the US administration in the controversial 2003 invasion of the country to oust Saddam Hussein.
The Labour government has long resisted calls for a formal inquiry into that decision, but Brown's confirmation of an end to Britain's military presence has fuelled renewed calls for such a probe once troops are out.
David Cameron, the leader of the main opposition Conservatives, welcomed the withdrawal announcement but questioned why Brown had not announced a "robust, independent inquiry" into the war.
But Brown insisted that the question of an inquiry would only be considered "once our troops have come home".
A total of 178 British soldiers have died in Iraq since the invasion, including 136 from hostile action.
Meanwhile the British leader is under growing pressure to send more troops to Afghanistan.
Britain has around 8,000 troops there as part of the NATO-led International Security Assistance Force (ISAF). They are largely based in Helmand, where they are battling Taliban insurgents.
On Monday Brown confirmed that Britain had sent an extra 300 troops until next August, while US president-elect Barack Obama is expected to push for more troops there after taking power in January.
On Thursday Brown made no comment on shifting forces from Iraq to Afghanistan, adding that it was wrong to compare the two missions.
"It is unrelated to any decision we make in Iraq," he said.
In Iraq on Wednesday, Brown said the four key British military objectives required before the pullout had been nearly fulfilled.
These are training the Iraqi army in Basra, transferring Basra airport to civilian use, aiding local economic development and providing support for Iraq's January 31 provincial elections.
British troop numbers in the Iraq campaign peaked at 46,000 in March and April 2003 for the invasion.