LONDON — This is a curious election for anyone who cares about Britain. If David Cameron, the Conservative prime minister, is returned to office, the country will face a referendum in 2017 that could take the United Kingdom out of the European Union and into strategic irrelevance. Two years will be lost to a paralyzing debate in which the worst of anti-European British bigotry will have free rein.

If Ed Miliband, the Labour Party leader, becomes prime minister, he will have in some form to rely on the support of the surging Scottish National Party (S.N.P.), which wants to break up Britain. Miliband vows that he will not succumb to the whims of Nicola Sturgeon, the S.N.P. leader, but this is a man whose determination to reach Downing Street has already seen the political equivalent of fratricide. His promises should be viewed in that cold light.

Pay your money and take your pick: a Britain outside Europe or a rump Britain. Of course, it’s not that simple. Cameron could prevail in his muddled attempt to keep the country in Europe while “repatriating” greater, as yet unspecified powers from Brussels. He may control the malign little-England genie he’s let out of the bottle to appease the right of his Tory party. Miliband may be able to make use of the S.N.P. without becoming its hostage. The worst is not inevitable.

Still, these unhappy choices point to an uneasy and divided Britain. Cameron has overseen an economic recovery that is the envy of continental Europe. Unemployment is at its lowest rate in several years. Jobless French and Spanish youths flock to Britain to find work. The prime minister has steadied the ship.

Very few, however, are partying aboard. The recovery has not translated into a sense of well-being or confidence. Income disparity is growing. Booming, purring London, with its glittering central districts full of bivouacked billionaires excavating ever deeper basements for their staff, has left the rest of the country behind and become a resented symbol of division. The S.N.P. has done very well out of its portrayal, however skewed, of a Tory anti-European England given over to ruthless free enterprise and Mammon.

The election on Thursday will be close. A hung parliament, as in 2010, appears likely, with no single party able to command a majority in the 650-seat House of Commons. British politics are taking an Israeli turn. The vote itself is a mere prelude to the real business of coalition building.

Most polls show the Conservatives with a slight lead, gaining about 35 percent of the vote and perhaps 275 seats, with Labour at 34 percent and about 267 seats. The phenomenon of the election seems certain to be a big S.N.P. jump to as many as 50 seats from the party’s current six, as if the rejection in last year’s referendum on Scottish independence merely freed the Scots to vote their heart without suffering the consequences.

Because the S.N.P. might cooperate with Labour but not with the Tories, Miliband may be in a stronger position than Cameron to form a government. The far-right U.K. Independence Party, whose influence on Cameron’s politics has been significant, will not, it seems, get more than four or five seats. The Liberal Democrats, who have governed with the Conservatives without their allegiance becoming irreversible, will take most of the rest, but many fewer than in 2010.

Cameron has led an odd campaign, so lusterless and absent at times that he could not even remember the name of his own football team. When he has found his voice, it has been in the name of free enterprise, as when he told a gathering of chartered accountants his was the party of the “techies, the roof tilers, the retailers, the plumbers, the builders” and vowed that what pumped him up was “taking a risk, having a punt!”

Beyond that, however, it’s anyone’s guess what Cameron really believes in. His gamble with European Union membership has been reckless and unpardonable. As yet, he has not given a single credible account of what it is he wants from Europe or why he has promised a referendum. In so doing, he has put Britain’s future at risk.

Miliband is a work in progress but his instincts are right. He will not hold a referendum on Europe. Beginning with his determination to abolish the non-domicile rule that, after the payment of an annual fee, permits many of Britain’s richest permanent residents to avoid paying U.K. tax on their worldwide income, he has shown an understanding that something must change to rebalance British society.

He has lambasted the “idea that says anything goes for those at the top, that what is good for the very rich is always good for Britain.” This disquiet over a money-driven culture is shared by a majority of the still-united British people. Miliband may prove the unlikely standard-bearer of that sentiment, all the way to Downing Street.