U.K. elections can be brutal affairs.

The polls close at 10 p.m. local time. Within hours the movers can be parked outside Number 10 Downing Street waiting to ferry away the losing prime minister's belongings. There's no U.S.-style 10-week transition here.

Since World War II, elections have led to eight changes in power, mostly conducted in an orderly fashion. In his landslide victory in 1997, Tony Blair gave his maiden speech as premier in front of the famous black door by lunchtime the day after the election.

But May 7's general election looks like it's going to be the most uncertain in the postwar period and the process of forming the next government could take days, if not weeks.

The traditional two-party system that's dominated British politics since 1945 is fraying like never done before with the Scottish National Party, for one, widely tipped to make big gains in the north.

Others, like the Green Party and the UK Independence Party, are looking to make a dent too, while the Liberal Democrats are hoping to remain a sizeable presence in Parliament despite widespread anger at the decision to link-up with the Conservatives after the 2010 election. And, there are Welsh nationalists and an array of Northern Ireland parties to account for, too.

With neither the Conservatives nor Labour predicted to win a majority of the 650 seats to the House of Commons, another coalition government, possibly involving three or more parties, is a possible outcome.

There's even talk that one of the big two parties may look to govern alone without a majority. The last time there was a so-called minority government after the election was in 1974, under Harold Wilson's Labour leadership — another election later in the year saw Labour win a slim majority.

Though polls at the moment suggest that David Cameron's Conservatives may win the most seats, they also suggest that Ed Miliband's Labour Party may have more options available to form the government once all the votes have been counted.

Whose face will be beaming at the famous black door in Downing Street is anyone's guess.

This photo gallery showcases some of the most memorable moments in British electoral history as captured by The Associated Press — from Winston Churchill's stunning defeat in 1945 to Cameron's arrival in 2010 after days of tortuous coalition negotiations.