LONDON - Cheers and shouts of joy erupted in central London Wednesday as hundreds of Americans who had waited all night celebrated the election of their first black president, Barack Obama.

Surrounded by US flags, eating hot dogs and knocking back bottled beer, they had anxiously watched election results filter in from across the Atlantic through in Yates' bar in the Leicester Square nightclub district.

When Obama's victory was announced, the largely Democrat crowd erupted into chants of "yes we can!" - the president-elect's slogan - and hugged each other in celebration at what many saw as a new page in US history.

"It's amazing," said Philip Kong, from Massachusetts. "A lot of hard work as come to fruition. He has remade the American political map."

"This is not just the first black American president, this is the first black leader of the free world and that's huge." David Grey, one of the reported 250,000 Americans living in the British capital, said that an Obama victory would make it easier for US citizens abroad by offering a better image of their country.

"It would be nice to have a president who is celebrated when he goes abroad and his effigy is not burned," he said.

Republicans were thin on the ground in the 500-strong crowd that gathered to watch the drama unfold, paying 35 pounds (40 euros, 55 dollars) each to attend a party dubbed as the second largest in London after the US embassy
bash.

Staff noted that while several different patterns of Obama's clip-on shirt button had sold out, McCain buttons had been outsold by those for libertarian candidate Bob Barr.

But most Democrats were cautious about Obama's prospects, barely daring to hope that he might win after eight years of Republican President George W. Bush.

"There is no way in holy hell I would have voted for McCain," said Shelley Morin, an American student from Washington state who is studying at Goldsmith's College in London.

She had expressed caution that Obama could win, saying: "I'm actually less concerned about Obama genuinely not winning enough electoral votes, than I am about (voting) machines, (misleading opinion) polls, lawsuits."

That concern was laid to rest Wednesday, as McCain formally conceded defeat.

British left-wing commentator Mark Steel was among many Londoners who joined the party because they couldn't bear to be left out.

"It's such a big night, it's huge. I just wanted to come and be a part of it," he told AFP, adding: "It shows you can change the world from below."