Final pitch in UK election cliffhanger

Britain's political leaders launched their last day of campaigning Wednesday for the most unpredictable election in living memory which could yield no clear winner and weeks of haggling over the next government.

With neither Prime Minister David Cameron's Conservatives nor Ed Miliband's Labour expected to win a majority on Thursday and smaller parties on the rise, the election could confirm a shift to a fragmented style of politics more familiar in other parts of Europe.

A Conservative win would raise the risk of Britain exiting the European Union because Cameron has promised a referendum on membership, while some business leaders and investors have warned Labour could be bad for the economy.

EU's foreign policy chief Federica Mogherini said in a speech in Peking University that the UK will remain an EU member, as it's in the UK's national interest.

Deputy Prime Minister Nick Clegg, leader of the centrist Liberal Democrats who have been in coalition with the Conservatives for the last five years, has even suggested there could be another election this year.

Cameron and Miliband, whose parties are virtually tied in opinion polls, have both embarked on frenetic tours of the country in a last-minute scramble for votes.

"This has been a remarkable election," Professor Tony Travers of the London School of Economics said, predicting that it would lead to some form of multi-party government "probably less stable than the one that formed in 2010."

Both Cameron and Miliband insist they are still fighting for a clear majority in the 650-seat House of Commons which would let them govern alone, but attention is increasingly turning to alliances they could make with smaller parties.

Cameron seemed to acknowledge the possibility of a fresh coalition or minority government in an interview with BBC radio. "People know that in 2010 we didn't win a majority, I put the country first, I formed the first coalition government for 70 years because I wanted to provide a strong and stable government for Britain," he said.

His Conservatives look well placed to team up again with Clegg's Liberal Democrats, assuming the Liberal Democrat leader can hold on to his own tightly fought seat in Sheffield, northern England.

While Miliband has ruled out a formal deal with the pro-independence Scottish National Party (SNP), it is thought they could still prop up a minority Labour government on a vote by vote basis. He told the BBC he was "not countenancing defeat" in the election.