LONDON (Agencies) - Presidential contender Barack Obama on Saturday defended his decision to travel to Europe and the Middle East, saying that problems encountered by Americans at home are often best dealt with by working with allies overseas. Obama, who spoke to reporters after wrapping up talks with British Prime Minister Gordon Brown, said he wasn't sure if there would be any immediate political impact from the trip - and that he wouldn't be surprised if there was a dip in some of the polls in the week since he left home. People in the US, he said, are worried about gas prices and home foreclosures. "The reason that I thought this trip was important is that I am convinced that many issues that we face at home are not going to be solved as effectively unless we have strong partners abroad," he said. "And unless we get a handle on Iraq and Afghanistan, not only are we going to be less safe, but it's also going to be a huge drain on resources." Obama said he and Brown discussed a wide range of issues, such as climate change, terrorism and financial markets. "The prime minister's emphasis - like mine - is on how we can strengthen the trans-Atlantic relationship to solve problems that can't be solved by any single country individually," he said. The Democratic hopeful seemed relaxed as he strolled down to the prime minister's office at 10 Downing St, pausing briefly to shake the hands of two somewhat startled police officers standing near the door. He turned to television cameras, smiled, waved and said "hello" before walking into Number 10. Brown greeted him just inside the door. Pooled television images showed Brown offering Obama a chair on the Downing Street terrace before the pair settled down for two hours of talks. Obama stressed the importance of the bond between the two nations. "We've been through world wars together. We speak a common language. We share a belief in rule of law and due process," he said "We just like the people. There is a deep and abiding affection for the British people in America and a fascination with all things British that's not going to go away any time soon." The Illinois senator also offered reassurance to Brown, whose plummeting popularity took another hit this week when he lost a parliamentary by-election in a Scottish seat long held by the governing Labour Party. But Obama pointedly said Brown didn't need his political advice. "You're always more popular before you're actually in charge," Obama said. "Once you're responsible, then you're going to make some people unhappy." From 10 Downing Street, Obama met with Conservative leader David Cameron for a postcard moment, posing for photographs in front of Big Ben and the Houses of Parliament. Earlier, he met with former Prime Minister Tony Blair, who is now a Middle East envoy. The meeting lasted for just over an hour. "They exchanged views on the situation in the Middle East and its wider implications, in light of senator Obama's visits this week and Mr Blair's continuing efforts to promote peace and prosperity," Blair's spokesman said. Blair represents the Middle East Quartet - the European Union, Russia, the United Nations and the United States - which is driving negotiations for a lasting peace deal between Israel and the Palestinians. Obama is winding up an election-season trip, financed by his campaign. Part of his goal for the trip through Afghanistan, the Mideast and Europe has been to allow him to make his debut on an international stage in the hopes of reassuring skeptical voters in the United States about his readiness for the presidency.