Blair resigned as prime minister Wednesday after a decade in power - heading for a new role in the Middle East while Treasury chief Gordon Brown succeeds him. Blair held a 25-minute meeting with Queen Elizabeth II to tender his resignation and is expected to quit as a lawmaker later in the day to take up his post with the Quartet of Mideast peace mediators. Brown, a 56-year-old Scot known for his often stern demeanor, beamed as he was applauded by Treasury staff before heading with his wife, Sarah, to the palace to be confirmed as prime minister. A visibly emotional Blair used his final weekly questions session with legislators to say sorry for the perils faced by British troops in Iraq and Afghanistan, but gave no apology for his decisions to back the United States in taking military action. "I wish everyone - friend or foe - well," Blair said before departing the chamber to cheers. "And that is that. The end." Legislators rose to their feet and gave the outgoing leader rapturous applause as he left the House of Commons chamber to head to a meeting with Queen Elizabeth II. Some, including Foreign Secretary Margaret Beckett, dabbed at tears. US President George W. Bush paid a final tribute to his ally and will later call Blair's successor with congratulations. "Tony's had a great run and history will judge him kindly," Bush told Britain's The Sun tabloid in remarks published Wednesday. "I've heard he's been called Bush's poodle. He's bigger than that." Bush is thought to have been instrumental in winning Blair his new role as envoy to the Quartet of Mideast peace mediators. Irish leader Bertie Ahern said Blair had told him the job would be "tricky," but said he wanted to focus on peacemaking. Protestant firebrand Ian Paisley, the Northern Ireland cleric and legislator who Blair persuaded to work alongside the territory's Catholic minority - achieving peace after decades of bloodshed, also paid tribute in the House of Commons. The departing chief faced "another colossal task" as a peace envoy, Paisley said, adding he hoped Blair's success in Northern Ireland would be repeated. Incoming leader, the taciturn Treasury chief Gordon Brown was summoned to the Queen's private quarters shortly after, where she will formally confirm him as prime minister during a closed-doors audience. Blair was heading to northern England, where he has called a meeting with officials in the area he represents to resign as a British legislator, his staff said. Brown was preparing to begin the job he's long waited to hold. The Scotsman must woo Britons by shaking off the taint of backing the hugely unpopular Iraq war. With promises of restoring trust in government, he is planning to sweep aside the Blair era after a decade waiting for the country's top job. Brown must also seek to head off a challenge from a revived opposition Conservative party. Polls already point to a "Brown bounce," with one survey putting his Labour party ahead of its rivals for the first time since October. Few expected the former finance chief to be greeted with public enthusiasm. In fact, Brown's ascension was widely seen as a political gift for the more affable Conservative chief Cameron. But Blair's last full day in office brought an unexpected present - the defection of a Conservative legislator to his Labour party. The move put Brown in bullish mood and he will now weigh calling a national election as early as next summer. Most keenly watched will be Brown's policy toward Iraq. British troop numbers there have rapidly fallen during 2007. Blair has left his successor an option to call back more of the remaining 5,500 personnel by 2008, an opportunity likely to be grasped by a leader with a national election to call before June 2010. Brown said Wednesday he would soon authorize the withdrawal of an additional 500 soldiers. "His hands, whilst not quite clean, are certainly not sullied," said Alasdair Murray the director of CentreForum, a liberal think-tank. Brown can "portray it as Blair's war and differentiate himself." The succession of Brown ends a partnership at the pinnacle of British politics that began when he and Blair were elected to Parliament in 1983, sharing an office and a vision to transform their party's fortunes. It has been widely reported but never confirmed that the two men agreed a pact over dinner in 1994: Brown agreeing not to run against Blair for the Labour leadership following the death of then party chief John Smith. In return, Blair reportedly vowed to give Brown broad powers as Treasury chief and to step down after a reasonable time to give Brown a shot at the senior post.