British Prime Minister Gordon Brown announced in the House of Commons that the country's military contingent in Iraq would be significantly decreased from 4,100 soldiers to less than 400, who would remain to train Iraq's naval staff.
"The fundamental change of mission ... will take place at the latest by May 31, 2009," the prime minister said.
The timetable is in line with a bill approved by the Iraqi government calling for all foreign troops except for U.S. forces to end their missions by the end of May and pull out entirely by the end of July.
The announcement came just after Brown's one-day trip to Iraq on Wednesday, where he met with Iraqi leaders in Baghdad as well as U.K. forces in the south of the country. He told Iraqi PM Nouri Maliki in Baghdad that British troops would leave by the end of July.
The withdrawal of British troops from Iraq's southern city of Basra, where most of the country's soldiers are located, became possible only after reaching significant progress in the areas of security, democracy and economic renewal in Iraq, the prime minister said.
"The level of violence in the region of Basra has significantly decreased over the last year," said the prime minister. He also added that while in Iraq he had met with heads of the Iraqi army and security forces. He also said that British training for the Iraqi staff had seen significant progress and was nearing completion.
British troop numbers in the Iraq campaign peaked at 46,000 in March and April 2003 during the U.S.-led invasion that toppled Saddam Hussein.