 World trade powers must agree on the headline figures for a long-delayed global free trade deal within the next three weeks or the current round of talks will fail, British Prime Minister Tony Blair said on Monday. Blair said he still thought it possible to get a deal on the World Trade Organisation's Doha round, but that failure to do so would be a blow to confidence in world trade. "The reality is that if we don't get ... the headline agreement in the next two to three weeks then we won't do it," he told a meeting of European business leaders in London. "If we don't agree very soon the headline numbers on this, then there won't be time to do this deal ... I still think there is a possibility of getting there." Blair is due to resign on June 27, handing over to finance minister Gordon Brown. Ministers from the United States, the European Union, India and Brazil said on Friday they were still confident of wrapping up the Doha round by the end of 2007. The four countries, known as the G4, have picked up the pace of negotiations ahead of a crunch time for the round in late July or early August. That is when a blueprint of a deal needs to be agreed by the WTO's 150 members to meet the year-end goal. If they do not meet that target, the accord is likely to be delayed by several years as US presidential elections in 2008 and elections in India in 2009 prevent governments from making politically sensitive concessions on trade, officials warn. Agriculture is a sticking point for the Doha round, which was launched in late 2001. Washington faces calls to offer far deeper subsidy cuts but says developing nations must open up their markets more. Blair, who discussed world trade with Bush in Washington last week, said: "I think America does want a deal, I think Brazil is anxious for a deal and I think for Europe it's really in our interests to have a deal -- even what is on the table at the moment would be a significant step forward." But he added: "In Europe and the US at the moment there are protectionist forces that are really quite strong." Blair also said he was optimistic of a deal on cutting greenhouse gas emissions to stop climate change at a summit of the Group of Eight industrialised nations in Germany in June. "I can't say at this point if we'll succeed in Germany in a couple of weeks' time, but I think it is possible," he said. He said the US administration was "looking to see whether it's possible to find a basis for a global deal" and that recent contacts with China and India had suggested they were more in favour of a global agreement than before.