What is a hung parliament, what happens next and will Jeremy Corbyn become prime minister?

Is the UK on course for its second coalition government in just a few years? Not necessarily...

The 2017 general election has delivered a result few expected - a hung parliament. With just seven seats still to declare, the Conservatives have 313 seats to Labour's 260. The SNP are on 34 and the Liberal Democrats 12. But what does it mean, and what happens now? Could Jeremy Corbyn become Prime Minister, or will Theresa May remain in Number 10?

What is a hung parliament?

When no political party wins enough seats to secure a majority in the House of Commons, the outcome is known as a hung parliament. With 650 MPs sitting in Westminster, a party needs to win at least 326 seats to be sure of a majority. The 2017 general election result means no one party has passed that threshold; the Conservatives have so far won 313 seats and Labour 260.

The UK’s first-past-the-post electoral system means hung parliaments rarely happen in Britain, but it was the case following the 1974 election and most recently, of course, in 2010.

In the case of a hung parliament, the leader of the party with the most seats is given the opportunity to try to form a government. This can take two forms: one option is a formal coalition with other parties, in which the coalition partners share ministerial jobs and push through a shared agenda. The other possibility is a more informal arrangement, known as “confidence and supply”, in which the smaller parties agree to support the main legislation, such as a budget and Queen’s Speech, put forward by the largest party but do formally take part in government.

What happens now?

The Conservatives have won the most seats by some margin. As a result, and as the incumbent, Theresa May will now have the chance to try to form a government. She could attempt to scramble together a formal coalition of other parties, most likely the Northern Irish DUP, that would take her over the threshold needed to obtain a House of Commons majority. Alternatively she may try to lead a minority government if she can convince other parties to back her in a vote of confidence.

Either way, it is difficult to see how Theresa May will be able to remain as Conservative leader for long. She began the election campaign with a sizeable lead and was widely predicted to extend her majority. However, a lacklustre campaign and criticism of the Prime Minister has denied the Tories the majority that once looked so certain.

Should Ms May prove unable to form a government that can pass key laws when Parliament meets on 13 June, Jeremy Corbyn, as leader of the second biggest party, would then be given the opportunity to govern.

He would most likely attempt to do so as leader of a minority government, with the Lib Dems, SNP and Greens backing him on issues, such as Brexit and the economy, where they have shared ground.

What have the other parties said about a possible coalition?

The Liberal Democrats have consistently ruled out any coalition, creating the possibility of neither the Conservatives nor Labour being able to secure the parliamentary numbers need to guarantee a majority in the House of Commons.

Former Lib Dem leader Sir Menzies Campbell re-iterated the party's position on Thursday night, telling the BBC: "Tim Farron made it very clear: he said no pact, no deal, no coalition. We’ve had our fingers burned by coalition, I don’t need to tell you that."

"I find it very, very difficult to see how Tim Farron would be able to go back on what he’s previously said and indeed to persuade the membership of the Liberal Democrats that a coalition would be a good idea from our point of view."

The SNP has shown more openness towards the idea of coalition government. Nicola Sturgeon, the party's leader, previously told the BBC: “If there was to be a hung Parliament of course we would look to be part of a progressive alliance that pursued progressive policies.”

That will come at a cost, though – likely to be a guarantee from whoever is Prime Minister that they will allow a second referendum on Scottish independence.

Green Party co-leader Caroline Lucas has also said she would be willing to enter a coalition with Labour.

How long will it take to sort out?

No one knows. Negotiations will likely begin immediately, with the Conservatives assessing whether they can assemble the number needed to pass legislation and survive any vote of confidence.

Theresa May is likely to argue that such an arrangement is crucial to the national interest, with Brexit negotiations due to start in just 11 days’ time, although it is highly possible that those talks will now be delayed.

In 2010 it took five days for the Conservatives and Lib Dems to negotiate a coalition agreement. Some kind of agreement will most likely need to be in place before Parliament reconvenes on 13 June.

What happens if no party can form a viable government?

In that situation there is likely to be a second election – possibly later this year. However, under the Fixed Term Parliaments Act, passed in 2011, that would require a two-thirds majority of MPs to vote for a second election.

Under the provisions of that act, if a government loses a vote of confidence then other parties get two weeks to try to form a government. Only if a second confidence vote is lost is an early election held.

What does this mean for Brexit?

It’s unclear. Whatever happens, it seems likely that the Brexit process will be held up and the eventual outcome of negotiations with the EU possibly altered. Apart from the Tories, almost all of the other parties are either opposed to Brexit or want a much softer Brexit than Theresa May has advocated. Ms May could be forced to change tack in order to, say, convince the Lib Dems to back her in a budget or Queen’s Speech vote. If she is unable to govern, a more pro-EU coalition incorporating Labour, the Lib Dems, SNP and the Green Party could be assembled to take Britain into talks with the EU.

The start of Brexit negotiations, scheduled for 19 June, could be delayed while a government is formed.