According to the latest polls, Conservative Prime Minister David Cameron and his Labor rival Ed Miliband are neck and neck ahead of today's general election.
Despite five weeks of campaigning, no party has won a clear advantage, predicting a potentially chaotic and uncertain outcome.
Reuters assesses that the stakes are high, given the rare combination of factors - Britain's future in the European Union and its national unity could depend on the result.
Cameron has promised to hold a referendum on whether to stay or leave the EU if he wins power again. And polls show the Scottish Nationalists could emerge as the third-largest party, even though they lost a referendum last year on whether Scotland should leave the UK.
"We can win an overall majority that will give Britain a strong, stable government that will continue with a long-term workable economic plan," Cameron said.
Miliband said his message to undecided voters was: “You can have another five years of a prime minister who puts the rich and powerful first in the country. Or if I become prime minister, my first priority will be the working people."
Britain got its first coalition government since World War II five years ago, when Cameron failed to win a majority and agreed with the Liberal Democrats to govern together and shore up the economy.
However, the rise of fringe parties such as the independence Scottish National Party and the anti-European UKIP has reduced support for the two main parties.
Polls published yesterday by Opinium and TNS showed that the Conservatives have a higher percentage than the Labor Party, Reuters reported. The ICM/Guardian survey gave 35 percent to both parties.
UKIP, which for much of the campaign rejected accusations of racism, was forced to suspend one candidate after he threatened to shoot a Conservative rival, a Briton of Asian descent, if he ever became prime minister.
Cameron combined a promise to improve standards with a warning that Scottish nationalists could blackmail the minority Labor government and force it to lean towards Scottish independence.
Miliband put the future of troubled healthcare at the center of the campaign.
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