Britain was weighing a beleaguered yet experienced incumbent against an untested but charismatic Conservative rival - along with a surprise upstart contender - in an election Thursday that was so close it could yield an uncertain outcome and prolonged political turmoil.
Labour Prime Minister Gordon Brown was trailing in the polls against Conservative David Cameron, with Nick Clegg of the perennial third-place Liberal Democrats gunning for a historic strong showing that could give his party major political clout.
But polls suggested there was a good chance no party would win an absolute majority needed to govern effectively.
The stakes are high: Britain is mired in economic crisis as its financial sector struggles to restore its luster, the nation creaks under mountains of public debt, and Greece's financial crisis threatens to spread across the continent.
A prolonged period of coalition horse trading and rudderless government could spook investors and send the economy into a downward spiral.
Brown doggedly stumped to the bitter end, pounding at the message that he's the safest pair of hands to lead his nation to economic recovery. Cameron finished off his campaign with a 36-hour marathon swing crisscrossing the country, hoping to bring the Conservatives back to power after 13 years in opposition.
The Liberal Democrats, the U.K.'s longtime third party, has found new momentum under the boyish, articulate Clegg - who has charmed voters by coming across as more natural than the aristocratic Cameron and friendlier than the notoriously grumpy Brown.
The 43-year-old political wunderkind seized upon sharp performances in the nation's first-ever televised debates to win attention and has capitalized upon voter mistrust following a lawmaker expense abuse scandal by promising lasting change.
Britain's tabloids started the day with the Daily Mirror running a picture of Cameron along with the words, "Prime Minister? Really?" The Sun, meanwhile, superimposed Cameron's face onto President Barack Obama's multicolored poster, with a headline that read "Our Only Hope."
Polls suggest the Conservatives will win the largest number of seats in the 650-seat House of Commons, but may well fall short of the 326 needed to form a majority government. If that happens - a so-called hung Parliament - Brown, as sitting prime minister, will get the first chance to form a government, even if Labour gets fewer seats than the Conservatives. He would likely try to do a deal with the Liberal Democrats.
Financial markets would likely react badly to the uncertainty of a hung Parliament, but many voters - disillusioned with busines-as-usual politics - would welcome it.
"Labour have done awful things, but I don't want a Thatcherite ... government, and I can't vote for the Liberal Democrats - they're weak Tories," she said, referring to the Conservatives by their common party nickname. "I'm just hoping for some sort of Labour-Lib Dem compromise, to water them all down."
Only months ago, most thought the election would be the Conservatives' for the taking - but that was before the perfect political storm started brewing.
An embarrassing expense scandal last year enraged voters after lawmakers were caught being reimbursed for everything from imaginary mortgages to ornamental duck houses at country estates, bringing trust in British politics to a record low.
And although lawmakers from all three parties were involved, the backlash was most severe for Britain's old guard, the Conservatives and Labour. Labour's popularity, slipping since Tony Blair's landslide victory in 1997, took a nose-dive after the unpopular Brown took the reins.
Then came the surprise success of Clegg, the son of an investment banker who called for an overhaul of British politics during the debates. His impressive performance thwarted Cameron and added to nagging worries over the extent to which the Tory leader actually overhauled the stodgy Conservatives.
The 43-year-old Cameron has also been hampered by his own elite background. Eton-educated and married to an aristocrat's daughter, many question whether he can relate to an electorate that has endured 1.3 million layoffs and tens of thousands of foreclosures over the past year and a half.
As Europe grapples with Greece's financial crisis, global markets are waiting impatiently for Britain's election outcome - anxious to know how quickly work can begin to cut the country's record 153 billion-pound ($236 billion) deficit.
A Conservative majority would likely lead to a stock market rally and a boost for the British pound because the Tories favor more aggressive, and immediate, cuts than Labour to Britain's deficit. But even a Labour majority could see a rally because it would erase market uncertainty.
The impact of a hung Parliament is far less certain.
Some analysts suggest fears about delayed action on the deficit could weigh on Britain's currency and stocks. Others say the markets have already factored that in and believe rapid action on the deficit is possible - as long as a new government is formed quickly.
If the Liberal Democrats are able to push through their main goal - overhauling Britain's centuries-old electoral system so it is more proportionate - the changes would favor center-left parties, and potentially shut Cameron's Conservatives out of power for decades.
This British election has already been historical. The country's first-ever television debates offered Clegg rare equal billing with Brown and Cameron, and he shone - combining his telegenic, friendly manner with sharp attacks on his rivals and the country's electoral system.
The Liberal Democrats - who have traditionally won about 20 percent of the vote since the party formed in a merger in 1988 - have held on to that unlikely surge although polls still put the Tories ahead but without a majority.
The same system that Clegg wants to overhaul, in which the number of districts won - not the popular vote - determines who runs the country, could produce the most bizarre election scenario. Labour could win fewer seats than the Conservatives, but still stay in power.
That's because convention holds that in the event of a hung Parliament, Queen Elizabeth II should offer the sitting prime minister the first chance to try to form a government - even if his party wins fewer seats than the opposition.
In such a scenario, Clegg could find himself with the balance of power. The backing of his expected bloc of about 80 seats in a coalition would give Cameron or Brown the ability to form a government and pass laws.
Without a firm mandate, the task for Britain's next leader of pushing through painful public spending cuts as well as a likely tax increase will be far more difficult.