LONDON -- Will Labour finish third yet end up with the most seats — then dump the leader who stumbled into unlikely victory? Will the rightwing Tories enter an awkward alliance with the center-left Liberal Democrats?
Could the ultimate fallout from Britain's election be the radical overhaul of a centuries-old parliamentary system in a nation that jealously guards its traditions?
Strange scenarios abound in Britain's unpredictable election, in which the Tories seem set to win the popular vote yet could end up with fewer seats than Gordon Brown's Labour Party — and the only good bet seems to be that the once innocuous Liberal Democrats will play the role of kingmaker.
"What we might be talking about is a once-in-a-century type of change, which is phenomenal," said Victoria Honeyman, a political analyst at the University of Leeds.
Labour, the main opposition Conservatives, and the election's unlikely insurgents, the once perennial third-place Liberal Democrats, are all expected to be denied an outright majority in the May 6 ballot — an unusual outcome that the British call a "hung parliament." UK elections haven't yielded one since 1974.
The frantic round of political bartering likely to follow, unfamiliar in Britain's usually clear-cut electoral system, could spark a shakeout that may oust party leaders, dismantle the two-party system, and lead to a historic electoral reform.
Polls suggest that Labour will fall far short of the Conservatives and may even be beaten by the Liberal Democrats — but, due to quirks in the electoral system, could still end up with the most seats in the House of Commons.
That would put Clegg in a quandary. Center-left Labour would be the Liberal Democrats' more natural ally, but teaming up with a discredited leader who lost the popular vote could be toxic.
One scenario being floated is that Liberal Democrat leader Nick Clegg, who shot to prominence on the back of stellar debate performances, would demand that the Brown step down in exchange for backing Labour.
Labourites would have a strong incentive to cooperate: Neal Lawson, head of Labour-affiliated think tank Compass, warned that the alternative was irrelevance.
"If we are now in an era of three party politics then the party that fails to build a partnership condemns itself to the wilderness," he said.
Another possibility is that — if Cameron wins a strong popular plurality — a movement could spring up around the idea that he has a "moral mandate" to rule. In that case Clegg may find it politically expedient to throw in his lot with the Tories — a result that would have the additional advantage of putting two youthful fresh-faced leaders at the top of government.
However, Cameron may balk at the price Clegg would likely demand for his backing. The Liberal Democrats want an electoral system of proportional representation — in which voters rank candidates in order of preference. That's the dominant system in Europe, where most governments involve coalitions.
The Conservatives fear such a system because it could go on to yield a perpetual Labour-Liberal Democrat alliance that could shut them out of power for decades.
In opposing proportional representation, Cameron points to Italy's raucous politics — warning that constant coalition building would result in "a bunch of politicians haggling, not deciding" on key policies, distracting from urgent economic repairs.
"If there is electoral reform, and that could happen, it would be extraordinary," said Honeyman. "The British constitution hasn't been changed like that since the 1920s."
Amid such tortuous political calculus, another unusual scenario looms: A round of coalition horsetrading among the parties could yield no deal — meaning Brown as a caretaker prime minister would be forced to call new elections.
Endorsing the Conservatives last week, The Economist, an influential weekly, acknowledged that, whatever the election result, a Labour implosion appears imminent.
"It is better for the country that Labour has its looming nervous breakdown in opposition," the publication stated in its leader column.
Despite his recent surge, Clegg is regarded — for now — as an unlikely contender to inhabit London's 10 Downing Street, even if he does seal a pact with a rival in the aftermath of Thursday's poll.
"The idea that you could see Nick Clegg as the next prime minister is about as likely as seeing fairies at the bottom of the garden — it's a nice thought, but it's not going to happen in reality," Honeyman said.