The polls have opened in Britain’s most unpredictable election in a generation, amid predictions that no single party would win enough support to govern Europe’s second-largest economy.

Despite months of campaigning, polls suggest that neither Prime Minister David Cameron’s Conservative party nor Ed Miliband’s opposition Labour has a clear lead, handing a potentially significant role to smaller parties — including Scottish nationalists or the right-wing U.K. Independence Party (UKIP).

Cameron’s Conservative Party entered a coalition deal with the center-left Liberal Democrats in 2010. The current prime minister is hoping for an outright victory this time around — but if his party falls short in this poll, Britain would be headed for only its second coalition government since World War II.

As many as one in four of Britain’s 45 million registered voters could still change their mind after polling began at 7 a.m. local time Thursday, according to one survey.

A YouGov poll published Wednesday put the Conservatives and Labour neck-and-neck at 34 percent of the vote, while a ComRes poll for the Daily Mail gave the Conservatives a slight lead at 35 percent against 32 percent. In both predictions, smaller parties hold the balance of power.

Two British newspapers, the Daily Mail and the Guardian, published tactical voting maps of Britain showing how local choices could change the national outcome.