One question is dominating Westminster today: Will there be a snap general election before Christmas?
European leaders are believed to be split on how long the UK’s departure from the EU should be postponed for.
Some believe a short extension of just a few weeks should be granted while others are in favour of a three month delay to January 31.
A final decision is expected to be made by the bloc tomorrow and what is decided will largely determine whether the nation goes to the polls in December.
Below is a breakdown of the different options available to the EU and what each could mean for the prospects of an election being held before the end of 2019.
When will the EU make a decision on a Brexit delay?
The EU is expected to make a final decision on the terms of the Brexit extension by close of play tomorrow.
At this point a Brexit delay is guaranteed because the bloc does not want to be blamed for a No Deal split on October 31.
But European leaders are divided on how long to push the divorce date back.
French president Emmanuel Macron is leading a group which wants a Brexit extension of as little as 15 days.
Belgium, Luxembourg and Spain are said to back Mr Macron – with the Netherlands reportedly drifting towards the same position.
But Germany and Ireland are among a large group of other countries that are more relaxed about the idea of a three month delay which was asked for by the UK Parliament and has the support of European Council president Donald Tusk.
Will there be a general election before Christmas?
This depends almost entirely on what the EU decides to do next.
A short delay would make an election before the end of 2019 unlikely while a long delay would make one more likely than not.
Boris Johnson, pictured in the House of Commons yesterday, is waiting for the EU to make a decision on a Brexit delay before making his next move
Donald Tusk, the president of the European Council pictured in Strasbourg yesterday, favours pushing back Brexit to January 31
What happens if the EU opts for a short delay of just a few weeks?
A short delay would make it difficult for Mr Johnson to push for a general election but it would provide him with more time to try to get his Brexit deal through the Commons.
MPs backed his deal on Tuesday but then voted against his plan to crash key Brexit legislation through the Commons in just three days.
A short delay beyond Halloween would allow Mr Johnson to give MPs more time to scrutinise the Withdrawal Agreement Bill – the legislation needed to make Brexit happen – and if it was passed the UK could leave the EU by the middle of November.
Mr Johnson could potentially swallow such a delay on the grounds it would give MPs one last chance to make a final decision.
If MPs failed to play ball and tried to further delay the UK’s departure from the EU, the PM would at that point have no choice but to push for an election.
The EU would then likely grant a further delay to avoid a No Deal split and make time for a snap poll to take place.
What happens if the EU opts for a long delay to January 31 next year?
This would almost certainly prompt the PM to try to trigger a pre-Christmas general election.
A long delay would strike a hammer blow at the heart of his ‘do or die’ pledge to deliver Brexit with or without a deal on October 31.
The EU is likely to include a termination clause in any such extension which would allow the delay to end as soon as a deal has been agreed.
But the prospect of telling voters that the headline date on the extension is January 31 would be unacceptable to Downing Street.
In such circumstances the PM will likely table a motion under the Fixed-term Parliaments Act 2011 demanding an election.
How would an election be called?
The PM would ask the House of Commons to vote on the FTPA motion. It would require the support of two thirds of MPs in order to succeed.
Mr Johnson has gone down this path twice before but he was thwarted on both occasions by opposition MPs.
If he was able to get the support of two thirds of the Commons the nation would then be on track for a snap poll at some point in the first half of December.
However, success or failure on the FTPA motion vote will almost certainly depend on what Labour decides to do.
Will Labour back holding an early election?
When Jeremy Corbyn blocked the PM’s last two tries to force an election he said that he would agree to go to the country early as soon as a No Deal Brexit has been ruled out.
If the EU offers a delay to January 31 next year then that threat of a chaotic split from the bloc will have evaporated and in theory Mr Corbyn should back an election.
However, he is under growing pressure from senior figures within Labour to block an election and instead push for a second referendum.
There are major fears among Labour MPs that the party would be decimated at a snap poll because of its policy of staying neutral on Brexit.
But Mr Corbyn is believed to be winning the battle and his spokesman as well as a number of his allies made clear yesterday and today that he will back an election once No Deal is ruled out.
If Jeremy Corbyn formally backs an election does that guarantee one will happen?
No and for a very simple reason. Even if Mr Corbyn says he wants his MPs to vote for a snap poll there is no guarantee that they will obey him.
In fact, recent reports suggest that a majority of Labour MPs intend to vote against a FTPA election motion – such is their level of concern about going to the country before Brexit has been resolved.
Jeremy Corbyn, pictured in the Commons yesterday, has previously said he will support an early election once a No Deal Brexit has been ruled out
If a major Labour rebellion did happen it could be difficult, but potentially not impossible, for Mr Johnson to hit the two thirds support threshold he would need.
What happens if most Labour MPs do vote for an election?
There will almost certainly be a snap poll held before Christmas. Such an election is likely to be a nightmare to plan and the later in December it is held the more difficult it will be to stage.
The government has been warned that anything past the middle of December would not be feasible because church and village halls will be booked up for nativity plays and parties and will not be available to act as polling stations.
What happens if most Labour MPs do not vote for an election?
There probably will not be a pre-Christmas election. In this scenario the UK would be stuck in Brexit purgatory.
Mr Johnson would likely have no choice but to bring back his Brexit deal to the Commons to try to get it agreed.
But his ‘do or die’ pledge would be in tatters and there would be no guarantees that Parliament would eventually agree to his divorce accord.
Is there any chance the UK will leave the EU on October 31?
There is now not enough time before Halloween for the PM to get his deal through Parliament.
But Mr Tusk has made clear that the EU will not allow a No Deal Brexit.
That means the October 31 deadline is effectively dead in the water and Brexit will be delayed.