Britain and Brazil agreed on Thursday to push for an ambitious reform of world trade rules and called for a summit of world leaders to thrash out the issues blocking a deal, according to Reuters. "We agreed to work together closely ... to try to persuade our partners and colleagues to go beyond the established positions and have a far more ambitious round," British Prime Minister Tony Blair told a news conference. "To that end, we are prepared to have a meeting of the key leaders and will discuss with our colleagues how and when that can be possible," he said after talks with Brazilian President Luiz Inacio Lula da Silva. He gave no further details. Time is running out for the 149-member World Trade Organisation to agree how to reform global trade rules under the so-called Doha round of talks, which started in 2001. The U.S. administration loses wide powers to negotiate trade deals in 2007 and without the world's biggest economy on board it would be far more difficult to get an agreement, Blair said. He argues a deal could lift millions of people out of poverty and deliver gains of up to $600 billion a year. "There is an absolute obligation and duty on us as an international community to find a way forward so the poorest countries of the world gain access to the markets of the more wealthy countries," said Blair. "However, it is also in the interests of wealthy countries to have a more open trading system." Talks have hit problems because developing nations want EU countries to lower farming subsidies while the United States and Brussels insist poor nations must open their markets to more non-agricultural goods. --SP 18 51 Local Time 15 51 GMT