After two delays to our leaving the EU, there's a question on a lot of people's lips - can Brexit be stopped?
The short answer is yes. It takes only a crucial few decisions to un-chisel the new October 31 exit date in stone.
But the long answer is it's complicated, very difficult - and despite everything, still may not happen.
Stopping Brexit altogether is a political choice that would involve reversing the result of the 2016 EU referendum, and both our party leaders say they don't want to do that.
The only exception is that Jeremy Corbyn might consider it in order to avoid crashing out with no deal.
Giving the public a vote that could stop Brexit seems more likely, but even then, even holding one will be an uphill struggle.
Delaying Brexit was always the most likely option, and has happened twice, but that won't stop us leaving the EU altogether.
So what are the options and what will they achieve? Here's a quick guide.
Brexit: EU net migration to UK falls to lowest level in a decade
1. Revoke Article 50
If she wants to, Prime Minister Theresa May can cancel Brexit with a stroke of her pen.
The 2016 EU referendum didn't, in itself, give any legal power for us to leave the EU.
Mrs May had to do that by triggering our notification to leave under Article 50 of the Lisbon Treaty.
That started a two-year countdown clock which was originally due to end at 11pm on 29 March 2019. That was then extended to 12 April, then 31 October.
But the UK government can still revoke the Article 50 notification at any time before Brexit actually happens.
Courts have ruled that we can do this without asking permission from the rest of the EU - and more than 6million people signed a petition urging Mrs May to do so.
EU chief Donald Tusk said he "dreams" of the UK revoking Article 50 and staying in the EU.
LIKELIHOOD: Very small. Theresa May has said Brexit will not be cancelled while she remains PM. There's a slim chance it could happen under a different Prime Minister if the public votes for it.
Can we revoke Article 50 to cancel Brexit - and will it actually happen?
2. Delay Brexit - again
The UK has already twice delayed the March 29 date of Brexit - with permission from the other 27 EU countries.
And EU Council President Donald Tusk has not ruled out the prospect of a further delay after October 31.
Until late February 2019, Theresa May refused to delay Brexit at all.
But she bowed to pressure from Remain-backing ministers, and agreed to request one after her deal was voted down three times.
Mrs May suggested it would be an extension by up to three months, to the end of June.
But EU leaders overruled her and made the delay last until October 31, with a break clause in June to review progress.
LIKELIHOOD: Relatively high if there's still no agreement. Theresa May lost a lot of political capital delaying beyond June - but now there's not that much more to lose.
3. A second referendum
If MPs vote for it, the UK can have a second Brexit referendum.
This could either be a re-run of the Leave/Remain vote from 2016, or a choice between Remain and options like Theresa May's deal or No Deal.
Recently the primary option to emerge has been a "confirmatory" public vote on any Brexit deal that is agreed.
That would allow voters to choose between Remain, and the Brexit deal put before MPs.
The government claims it would take around a year to organise a second EU referendum - though supporters claim it could happen much more quickly.
And it would not be guaranteed to stop Brexit. Leave voters could vote in large numbers and deliver a second Brexit result, and public divisions would be likely to deepen.
LIKELIHOOD: Much more likely than in early 2019, after Labour committed to back a second referendum in Parliament and confirmed it was on the agenda in talks with Theresa May. But Jeremy Corbyn appeared reluctant to demand it as a condition for passing a Brexit deal.
What does Labour's Brexit announcement pushing for a second referendum mean?
4. A general election
So, this wouldn't actually stop Brexit.
But if Labour finally wins a vote of no confidence - or Theresa May decides to go to the country - we'll get a general election.
That would then open up a labyrinth of new possibilities, some of which could raise the likelihood of Brexit being delayed or stopped.
LIKELIHOOD: Unknown. Theresa May has said she won't call a general election but she's fooled us before. And for Labour to win a no confidence vote, the party would need the backing of the DUP (who seem very unlikely) and The Independent Group of MPs (who've signalled directly they won't back a no confidence vote).
5. Brexit... and then go back in later
In theory, Brexit could happen and then we reapply to join the EU like any other country.
But forget just the political heartache - some countries have spent years in the accession process.
This would be a hugely long-winded process. Don't expect it to bear fruit too soon.
