Could there be an early general election?
MPs have twice rejected Prime Minister Boris Johnson's call for an early general election on 15 October, ahead of a crucial European Union summit.
Why was Mr Johnson unable to call an election and what are his options?
Why does the PM want an early election?
Mr Johnson wants an early election to restore the Conservative Party's majority in the Commons.
While calling an early election carries risks, Mr Johnson would aim to end the political stalemate and make it easier to deliver Brexit.
Why did Mr Johnson lose last week's vote?
Prime ministers used to be able to call an early election at the time of their choosing. But under the Fixed Term Parliaments Act, Mr Johnson now needs the support of two-thirds of MPs - at least 434 - to trigger an early poll.
However, he no longer has a Commons majority.
Many MPs were worried that Mr Johnson would not stick to his pledge to hold the election on 15 October.
A motion, under the Fixed Term Parliaments Act, to call an early election does not specify the day it is to take place. MPs simply vote on whether they agree with the statement "that there shall be an early parliamentary general election".
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Senior Labour figures said they would not vote for an early election while there was a risk the prime minister could move the poll to after 31 October - by which point the UK would have left the European Union.
How soon could an election happen?
If enough MPs support an early election, the prime minister recommends the date of the poll to the Queen.
Parliament would then be dissolved 25 working days before an election takes place. At this point, politicians stop being MPs and they campaign for re-election, if they choose to stand again.
Now that Parliament has been prorogued - that is, suspended - MPs will not have another chance to vote for an early election until 14 October, when they return. Were they to do so, the earliest an election could be held would be 19 November.
However, by convention members debate and vote on a Queen's Speech at the beginning of a new session of Parliament after prorogation.
This can take around five days, meaning the date for a new election would be later than 19 November.
Does the PM have other options?
While the Fixed Term Parliaments Act requires a two-thirds majority to sanction an early election, it is not impossible for a government to get round this requirement.
It could be achieved by introducing a very short law that calls for an election and adds "notwithstanding the Fixed Term Parliaments Act".
The advantage of this route, from the government's point of view, is that it would only require a simple majority of MPs to support it (more voting for than against) rather than two-thirds.
It would also allow an election date to be set in stone, which might make some MPs more likely to vote for it - although there is no guarantee the government would win.
However, this route would take longer. The proposed law would need to clear the House of Lords, as well as the House of Commons. Given that Parliament is due to prorogue (or shut down) this week, getting the legislation passed would be a race against time.
There is also a risk that the legislation could be amended - allowing pro-Remain MPs to make changes, such as forcing a further Brexit extension.
The government could also ask the Queen to end prorogation early and hold a vote as soon as MPs come back, although this seems unlikely.
There is a third, extremely high-risk option. If the government was absolutely determined to hold an early election it could, in theory, call a vote of no confidence in itself.
If it chose to do this, MPs would have to decide whether they want the current government to continue.
If such a vote passes, opposition parties would be allowed two weeks to come together to try to form an alternative government. If this happened, Mr Johnson would be expected to resign and a new prime minister could request a further Brexit delay to prevent a no-deal outcome.
But, if nothing is resolved after 14 days, a general election is automatically triggered.
However, this would be a high stakes strategy, as it completely relies on opposition parties failing to form an alternative government.
Catherine Haddon, from the Institute for Government think tank, says the chances of the government calling such a vote are "extremely unlikely".
"From a political point of view, calling a vote of no confidence in yourself would look mad," she says.