LONDON — British voters appear set to usher in the most divided parliament in generations, potentially ending the two-party dominance that has defined modern Britain and challenging the ability of the next government to tackle a financial hole that rivals the one in Greece.
For the first time since the 1970s, neither the Conservatives, who last held power in 1997, nor the ruling Labour Party is poised to win an outright majority in Thursday's vote. Given the missteps by Prime Minister Gordon Brown — who called a widowed retiree a bigot in off-camera remarks last week — Labour in particular is bracing for what may be its biggest defeat since 1983, when Margaret Thatcher won a second term and the party was exiled from No. 10 Downing Street for another 14 years.
But the shake-up at the gothic House of Parliament could be even more profound. A roiling expenses scandal in which British taxpayers covered the bill for duck ponds and pornography is fanning voter outrage against politics as usual, opening the door for fresh-faced Nicholas Clegg, leader of the typically also-ran Liberal Democrats. Clegg, 44, has surged in the polls and is pressing for electoral reform that could end the duopoly on British power.
In nearly any scenario, Britain will find itself in uncharted waters Friday morning, with major implications for the country's future.
"Things are really being shaken up," David Cameron, the Conservative leader, said in an interview with the Washington Post last week.
Current polling suggests that Cameron will probably have the first shot at forming a government. Although the Conservatives think they have a chance at winning an outright majority, it still appears likely they will need to forge alliances or even a coalition to rule.
That is largely because of Clegg's rise. He reached celebrity status during three U.S.-style televised debates, introduced in Britain this year. Though Clegg is coming off the highs of his initial surge, his Liberal Democrats are still polling so strongly that he could win more votes than Brown's flagging Labour Party.
Yet the vagaries of the current system mean that Labour could come in third in the popular vote, but still win the most seats through the grace of districting.
Clegg, whose newfound support is setting him up as kingmaker, is insisting on major electoral reforms as part of any promise to back Brown or Cameron. That could potentially thrust the issue, including doing away with the unelected peers in the House of Lords, toward the top of Parliament's agenda. Such a move would shift Britain away from its parallels to two-party politics in the United States, and toward continental European-style coalition governments.
It is not yet clear British voters are ready to make this leap. Britain cherishes stability, and Cameron in particular has rolled out scare tactics on the campaign trail, warning of a "horse-trading" Parliament paralyzed by bickering if swing voters don't give his Conservatives a clear majority. He has raised the specter of the weak governments and the political and economic crises that plagued Britain in the 1970s, warning of a debt crisis like Greece's that could cripple the pound and spark a run on British bonds.