Last chance for Cameron and Miliband to break UK election deadlock

Campaigning in Britain's most unpredictable election in a generation were finalized on May 6 with the two main parties level in most polls and neither on track to command a majority in the parliament of the world's fifth largest economy. 

Despite more than five weeks of campaigning, neither Prime Minister David Cameron's Conservative party nor Ed Miliband's  opposition Labour has established a clear lead, and the outcome of the May 7 vote could be messy and uncertain. 

The stakes are higher than usual because of a rare confluence of factors which mean Britain's future in the European Union, as well as its national cohesion, could hinge on the election outcome. 

Cameron has promised to hold a referendum on whether to stay in or quit the EU if he returns to power.

Polls suggest Scottish nationalists could emerge as the third largest party, despite losing a plebiscite last year on whether Scotland should break away from the United Kingdom. 

"The consequences if you take a wrong turn could at its worst - and I'm not predicting this - mean that within a matter of years, two unions which are pivotal to the prosperity and way of life of everybody in Britain are lost," Nick Clegg, the deputy prime minister and Liberal Democrat leader, told Reuters during the campaign. 

Five years ago, Britain got its first coalition government since World War Two when Cameron fell short of an overall majority and struck a deal with Clegg's centrist party to govern together to steady the economy. 

Many Britons thought that was a one-off. 

But the rise of formerly fringe parties such as the pro-independence Scottish National Party and the United Kingdom Independence Party (UKIP) has fragmented the political landscape,...