After failing twice to get her Brexit deal through Parliament, Theresa May is now requesting a short extension.
Assuming the other member states all agree, Brexit will be postponed. Theresa May has said she is not prepared to delay Brexit beyond 30 June.
The Speaker John Bercow has ruled that the PM can’t bring her deal back for a third vote without “substantial” changes. But it is widely expected that she will want MPs to vote again soon.
There are still plenty of possible outcomes.
1. No deal at a later date
Voting to delay Brexit would not mean that leaving the EU without a deal was ruled out forever.
If the EU won’t grant a delay, or if the UK and the EU cannot sign off a deal during any extension, then this would still be the default outcome.
So although a majority of MPs have repeatedly indicated they are against no deal they would need to do something else to prevent it from happening as a matter of course.
2. Further vote on PM’s deal
Theresa May could have another go at getting her deal through the House of Commons.
The government had planned to hold another vote before the EU summit on 21 March. But on 18 March the Speaker made a statement in the Commons arguing that there couldn’t just be a rerun of the vote on 12 March. There would either have to be changes to the deal or MPs would have to be asked to consider a different question.
There is a rule that the House of Commons should not be asked to vote twice on exactly the same question during a single parliamentary session.
It is up to the Speaker to decide whether to allow any vote.
If MPs do get to vote again at some point, and back the deal at the third time of asking, legislation would be introduced to bring it into effect with a new Brexit date.
3. Major renegotiation
If there was a longer extension at any point, the government could propose to negotiate a completely new Brexit deal – possibly after Parliament has had a chance to express its view about alternative proposals.
This wouldn’t be a question of carrying out minor tweaks and having a further vote.
Instead, there could be a complete renegotiation that would take some time.
The government could pivot towards one of the other models of deal that has been suggested – perhaps something close to the so-called “Norway model” which would involve a closer relationship with the EU than the current deal proposes.
If the EU refused to re-enter negotiations, the government would have to plump for one of the other options instead.
4. Another referendum
A further possibility is to hold another referendum.
It could have the same status as the 2016 referendum, which was legally non-binding and advisory – in common with past UK referendums. But some MPs want to hold a binding referendum where the result would automatically take effect.
Either way, a referendum can’t just happen automatically. The rules for referendums are set out in a law called the Political Parties, Elections and Referendums Act 2000.
There would have to be a new piece of legislation to make a referendum happen and to determine the rules, such as who would be allowed to vote.
It couldn’t be rushed through, because there has to be time for the Electoral Commission to consider and advise on the referendum question.
The question is then defined in the legislation.
Once the legislation has been passed, the referendum couldn’t happen immediately either. There would have to be a statutory “referendum period” before the vote takes place.
Experts at University College London’s Constitution Unit suggest that the minimum time for all of the required steps above is about 22 weeks.
5. Call a general election
Theresa May could decide the best way out of the deadlock would be to hold an early general election – in order to get a political mandate for her deal.
She doesn’t have the power just to call an election. But, as in 2017, she could ask MPs to vote for an early election under the terms of the Fixed Term Parliaments Act.
Two-thirds of all MPs would need to support the move. The earliest date for the election would be 25 working days later but it could be after that – the prime minister would choose the precise date.
6. Another no-confidence vote
Labour could table another motion of no confidence in the government at any time.
Under the Fixed Term Parliaments Act 2011, UK general elections are only supposed to happen every five years. The next one is due in 2022.
But a vote of no confidence lets MPs vote on whether they want the government to continue. The motion must be worded: “That this House has no confidence in Her Majesty’s Government.”
If a majority of MPs vote for the motion then it starts a 14-day countdown.
If during that time the current government or any other alternative government cannot win a new vote of confidence, then an early general election would be called.
That election cannot happen for at least 25 working days.
7. No Brexit
The European Court of Justice has ruled that it would be legal for the UK to unilaterally revoke Article 50 to cancel Brexit (without the need for agreement from the other 27 EU countries).
With the government still committed to Brexit, it’s very likely that a major event such as a further referendum or change of government would have to happen before such a move.
However, any delay to Brexit would certainly lead to questions about whether the ultimate destination was going to be a reversal of the 2016 referendum.
It’s not totally clear what the process would be. But an act of Parliament calling for Article 50 to be revoked would probably be sufficient.
After Theresa May survived a challenge to her leadership, the Conservative Party’s rules mean she won’t face another for 12 months.
But she could always decide to resign anyway, if she can’t get her deal through and she’s not prepared to change course.
That would trigger a Conservative leadership campaign which would result in the appointment of a new prime minister.
She might also come under pressure to resign if MPs pass a “censure motion” – that would be a bit like a no-confidence vote but without the same automatic consequences. Again this could lead to a change in prime minister or even a change in government.
Whoever ended up in charge would still face the same basic range of Brexit options though.