LONDON (AP) — Counting the votes in Britain's election will take a matter of hours. Assembling a government could take days — or weeks.

By Friday, the country will know how many seats each party has won in the House of Commons. If either the Conservatives of Labour has more than half the 650 seats, they can quickly form a government.

But almost no one thinks that will happen. Polls predict a "hung Parliament," in which no party has a majority, triggering an intense period of wrangling and uncertainty.

WHAT HAPPENS NOW?

In Britain's parliamentary system, the test of a government is whether it can command the support of the House of Commons. In theory, that takes 326 seats, but in practice it's about 323: the Speaker does not vote, and Irish nationalists Sinn Fein, who had five seats before the election, do not participate.

If no party has a majority, political leaders will negotiate to put together groupings that can secure a majority of votes.

There is no rule saying the party with the most seats gets the first shot at talking to other parties about forming a government, but there will be unofficial pressure for that to happen. Liberal Democrat leader Nick Clegg says he will speak first to the biggest party, although there are likely to be parallel and overlapping talks.

"I've described it like freestyle wrestling," said Peter Riddell of the Institute for Government. "Anyone can talk to anyone else, and it may well be that the second-largest party is in an easier position to form a government than the largest party."

Queen Elizabeth II formally appoints the prime minister, but her role is symbolic. Once the political picture is clear, current Prime Minister David Cameron will go to Buckingham Palace — either to tell her he can form a government, or to resign and ask her to summon Labour leader Ed Miliband.

HOW LONG WILL IT TAKE?

In 2010, it took five days for the Conservatives and Liberal Democrats to forge a coalition. Gus O'Donnell, who as Britain's top civil servant oversaw those negotiations, said that "was a piece of cake compared to what might happen this time."

"More options, more parties involved ... it is harder this time," he told the BBC.

Parliament is due to reconvene on May 18, when lawmakers will take their oaths and one will be elected Speaker. That could all happen without a government being in place.

A firmer deadline is May 27, the date set for the Queen's Speech. That is an annual address, delivered by the monarch but written by ministers, outlining the government's legislative program. It is followed by a debate and a vote — and it would be hard for a government to survive losing that vote.

IN THE MEANTIME, WHO'S IN CHARGE?

Win or lose, on Friday morning Cameron will remain Britain's prime minister. The current leader and his government will remain in place until a new one is assembled. Ministers are expected to defer major decisions, but handle routine business and emergencies.

Financial markets hate instability, so some fear the pound could take a pummeling if the talks drag on.

"There will be a strong civil service presence saying: 'Do you look at the markets? You had better get a grip. You'd better work something out,'" said Leeds University political scientist David Seawright.

Other analysts believe the markets have already factored in a period of uncertainty so are unlikely to be too volatile.

Riddell points out that protracted negotiations, while novel for Britain, are the norm in many European countries.

He said, "we won't be like Belgium," which went without a government for more than a year.

"The general view is, keep calm and it will work itself out."

WHAT ARE THE LIKELY OUTCOMES?

"It's unbelievable, the permutations," said Seawright. "It'll be musical chairs to see who can form a government."

Some of the potential options:

—The Coalition Continues: Britain could see a continuation of the Conservative-Liberal Democrat coalition that has governed since 2010. The Lib Dems are open to this option, and have campaigned as the sensible center ground between Tories on the right and Labour on the left. But the party is likely to lose a big chunk of its 59 seats. Still, a Conservative-Lib Dem coalition could probably rely for support on key votes from smaller parties including Northern Ireland's Democratic Unionists and the U.K. Independence Party.

—Lib-Lab Pact: Labour could try to form a coalition with the Liberal Democrats, who are sympathetic to them on some issues. Such an alliance could probably command support from small left-leaning parties including Wales' Plaid Cymru and the Greens.

—Labour and the SNP: This is one of the combinations most likely to add up to a Commons majority, but is politically fraught. The SNP, which is expected to take most of the seats in Scotland, supports Scottish independence, and its participation in national government has been painted by opponents as a threat to the future of Britain. Labour leader Ed Miliband has ruled out a coalition pact or broad deal with the SNP. But he also knows that the nationalists, who are staunch anti-Conservatives, would back Labour on key votes.

—Minority government: Either Labour or the Conservatives — whichever has more seats — could try to govern alone, relying on smaller parties for support on a vote-by-vote basis. Minority governments are often unstable, and sometimes fall within months. But Britain's political parties, with their members exhausted and coffers depleted, may be unwilling to trigger a second election this year. And recent legal changes have made it harder to bring down a government. Once, defeat on a major piece of legislation would have done it, but it now requires an explicit vote of no-confidence by lawmakers.

—Grand Coalition: Unlikely but not impossible is a coalition of traditional enemies Labour and the Conservatives. It has happened before, though only at a time of national crisis, during World War II. Some have argued that it is the best option to keep Britain united in the face of a fractured political system and growing separatist and anti-European sentiment.

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