White House hopeful Barack Obama has tried to comfort Gordon Brown over his plummeting popularity. Speaking outside No 10 following two hours of talks, the US Democratic presidential nominee said he had no words of advice for the embattled Prime Minister. He said: "You're always more popular before you're actually in charge. Once you're responsible then you're going to make some people unhappy." Mr Obama said he and Mr Brown had talked about strengthening the relationship between the US and Britain. He said he had thanked Mr Brown for Britain's "stalwart assistance" over issues such as Afghanistan and knew British troops had "borne a heavy price" while fighting the Taliban. The Illinois senator is committed to increasing the number of troops in Afghanistan if elected. But he hinted Britain will also be expected to offer support, saying: "We'd like that burden shared." He said his meeting with Mr Brown had been "wonderful" and said the two leaders discussed climate change,...