What if no-one wins the election?

What happens after the election if there is a hung parliament? Which parties might agree to work together and who may hold the balance of power? Who could build a majority of 326 votes in the house? Play our game to find out.

Reading on the BBC News app? Click here to play our hung parliament game.

*Each result is randomly generated and not a prediction of the election - read more.

What is a coalition?

A coalition is when two or more political parties agree to form a government that includes ministers from each party.

In general a coalition is formed because no single party has enough MPs to guarantee that their bills will be voted through by Parliament.

The coalition governing the UK for the last five years was the result of the Conservative Party gaining the largest number of MPs at the 2010 general election - but finding itself short of the 326 required for a majority in the House of Commons.

A coalition of the Conservatives and the Liberal Democrats was the only two-party combination able to command a majority.

Does there have to be a coalition?

A coalition is not the only option in a hung parliament. A government only has to show that it can "command the confidence of the House of Commons". This means being able to gather enough votes to defeat any vote of no confidence called by the opposition.

One party could decide to form a minority government, filling all the ministerial roles with its own MPs but relying on votes from outside the party to pass any bills.

How these votes are secured is up to the political parties. There are no rules on how they must draw up any agreement.

The outcome of discussions could be a formal pact, where the parties agree to vote together on all bills, or it could be that the government has to persuade other parties to vote with them on a case-by-case basis.

What is "confidence and supply"?

In the run-up to the election, several party leaders have ruled out joining a coalition and talked instead of having a looser agreement. This is sometimes known as a "confidence and supply" arrangement.

"Confidence" refers to the smaller party promising to support the government in any vote of no confidence called by other parties, while "supply" means that the party will help the government to pass its budget.

In practice, this means a minority government doesn't have to constantly worry whether it is about to be voted out of office. In return it will need to co-operate with other parties in drafting every bill that it wants to put before Parliament.

Who gets first chance to form a government?

A prime minister remains in office until he or she informs the Queen they are resigning, and is only "expected" to resign once it becomes clear that they cannot command a majority in the house.

So, for example, David Cameron is entitled to stay in power if he believes he can build a working majority. He then has just under two weeks to form a government before the the start of the new Parliament.

Should this happen, the opposition could then test the strength of his majority with a vote of no confidence.

Before and during the new Parliament, other parties may decide to join discussions with the present government, or the party with the most MPs, or the party with which they have the most policies in common.

Talks on forming a government may start between opposition parties even though the prime minister remains in power, which was the situation facing Gordon Brown in 2010.

How long do they have?

There are 12 days between polling day and the first meeting of Parliament, the exact date of which is set by Royal proclamation.

The date for the start of the next Parliament has already been announced as 18 May 2015.

In 2010, it took 13 days to complete the full coalition agreement between the Conservatives and the Liberal Democrats.

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