British Prime Minister Tony Blair paid a surprise visit to Iraq on Thursday, saying the country's security and political situation had improved over the last year, but refused to set a timetable for the withdrawal of British troops. "You don't set an arbitrary timetable," Blair said, briefing reporters at a British logistics base near Basra in southern Iraq. "The whole purpose is to build up the Iraqi security forces so we can draw down our own strength." Blair flew into Basra from Kuwait aboard a Royal Air Force Hercules transport plane for a morale-boosting pre-Christmas visit to some of the 8,000 British troops based in Iraq. Their presence, almost three years after the March 2003 invasion, continues to depress Blair's popularity at home. Britain's military contingent in Iraq, based around Basra, is the second largest after that of the United States. Ninety-eight British troops have died in Iraq since the invasion. Blair has repeatedly said British troops will not leave Iraq until they are asked to go by the Iraqi government. He said 100,000 Iraqi troops were now trained and ready to take over security duties. Gen. George Casey, the top US officer in Iraq, told Blair that by next summer, 75 percent of security duties in some parts of Iraq would be led by Iraqi troops. "The troops to whom I spoke here were rather more upbeat about the Iraqi capability than I had expected," Blair told British troops at Shaibah Logistics Base. "The important thing is to try and help this country become a democracy. The only way of doing that is to provide security so that the Iraqi forces can build up and then we can eventually draw down our own capabilities." Recently, Blair and senior ministers have spoken of reducing the number of British troops as early as March, after a permanent Iraqi government is installed following last week's election. During meetings Thursday with senior British and American military officials and diplomats, and in comments to the troops, Blair signaled milestones on the road to withdrawal. He hailed the results of Iraq's December 15 parliamentary elections, saying the country's security and political affairs were in "a completely different situation than the situation a year ago." He said it was crucial to get a "good, strong unity government out of the election," but said Iraq was closer to becoming a stable democracy than it had been before. "If we manage to defeat terrorism here then we will have dealt it a huge body blow worldwide," Blair said. "I know how dangerous it is sometimes but the one thing for sure is that when you look back on this time you will be very proud of what you have done." The pre-Christmas visit - Blair's fourth trip to Iraq since the 2003 invasion - was intended partly to thank the 8,000 British troops, who will be away from home over the holiday period. "I know it's difficult from time to time," he said, speaking to troops at the dusty desert base against a backdrop of tanks and armored vehicles. "But whatever the controversies are about the politics of the situation, people back home have the most enormous pride in our armed forces, and quite rightly, too. "This mission will, I think, be achieved successfully," he added. The administrations in Washington and London, facing persistent domestic opposition to the war, hope Iraq's parliamentary election will produce a stable government and pave the way for the withdrawal of some American and British troops. Blair's popularity has been battered by his decision to join the US-led invasion, and he has faced allegations that his administration exaggerated the threat posed by Saddam Hussein's alleged weapons of mass destruction to bolster the case for war. Blair's Labour Party was re-elected to a historic third term in May, but its House of Commons majority was slashed, partly as a result of opposition to the war. In the months after the 2003 invasion, British troops enjoyed relative peace in Shi'ite-dominated southern Iraq compared to the restive Sunni regions further north. But violence in the region has escalated. Roadside bombs and other attacks have killed 10 British soldiers in southern Iraq since May.