They may be exiles, but Americans in London exercise right to vote

(Carl De Souza/AFP/Getty Images)

Being Barack Obama's emissary in London is not without difficulties, Diana Shaw Clark admitted yesterday as she rallied the expatriate faithful behind the Illinois senator. "The challenge for me is that I am representing the most articulate candidate we have had in generations, so it is hard to do that adequately," she said.

For one day only, a draughty hall in Bayswater, west London, was transformed into a US election polling station yesterday, with balloons, free cup-cakes and a generous supply of Stars and Stripes flags. At 6pm, when the ballot opened, the queue of voters stretched around the block into Queensway.

By late last night, more than 1,000 expat Americans in London had turned up to make their votes count, and Ms Shaw Clark expressed relief that Mr Obama had won a landslide against Hillary Clinton. The initial result – voting online and by fax carries on for another week – showed Mr Obama had more than double Mrs Clinton's tally, winning by 998 to 433. An estimated 300,000 Americans live in Britain and both Democratic candidates had sent over their big guns to help raise their profiles among the expat community. Mrs Clinton dispatched her husband Bill, the former president. Mr Obama sent his wife, Michelle.

For turnout, the strategy paid off. The number of Democrats seeking to vote in the two UK primaries, the second of which is in Oxford today, has doubled in a month. The campaign group Democrats Abroad said it had counted two-and-a-half times as many voters this year as it did during the last election. British-based Democrats will send 22 delegates to the party's convention later this year – a privilege denied to overseas Republicans.

In total, six million expat Americans are allowed, for the first time, to vote online and by fax. Ms Shaw Clark believes it is a new era for her homeland. "I did not get in this race to back a winner, I got in it to fight cynicism," she said. "We have been able to take on the most famous candidate in US and close the gap."

Meanwhile, Margo Miller, a lawyer backing Mrs Clinton, played down any rift between the rival camps, saying: "We are first and foremost Democrats. But Hillary is still the most qualified candidate."

Barbara Lewis, a 64-year-old who has lived in Britain for 37 years, said she voted Obama after shunning previous elections. "This is the first time I have ever been interested to vote," she said, explaining her reasons for backing the Illinois Senator. "It is the man himself. The way he presents himself, the way he decides and the way he gives excitement to a whole range of people."

Although Republicans abroad could not vote last night, supporters said they were confident that whoever won their party's candidacy would go on to secure the White House.

Mary Jo Jacobi, a former presidential adviser to Ronald Reagan and George Bush Senior, predicted that the party would find it easier to mobilise against Mrs Clinton if she won the Democratic nomination. "[We] might be at a loss right now as to who to nominate but Hillary Clinton is a galvanising force," she said. "If she is at the top of the ticket, you can be assured there will be a strong Republican turnout."

For rolling comment on the US election visit: independent.co.uk/campaign08