28/03/2019 9:47 PM AEDT | Updated 29/03/2019 1:19 AM AEDT

What Happens Next In Brexit Now Theresa May Has Decided To Quit

Theresa May has promised to fall on her sword if MPs back her Brexit deal. The last ditch attempt to secure support and secure her legacy has won over many high-profile Tories. But it still might not be enough.

This is what could happen next.

When will the UK actually leave the EU?

For two years, the prime minister insisted Brexit would happen on March 29. This Friday. Now it will not.

If MPs vote in favour of the Withdrawal Agreement by the end of the week then exit day will be May 22. But if the deal is rejected - or not voted on - the UK will be on course to leave on April 12 without a deal.

May has said she will not lead the country out of the EU with no-deal unless parliament supports it. It will not. Therefore the PM is most likely to ask Brussels to grant an even longer extension to Article 50 while the UK works out what to actually do.

When Will Theresa May Bring Her Deal Back?

Friday – the original Brexit date – could be the day May tries to make it third time lucky for her beleaguered Brexit deal.

The Commons was not expected to sit on March 29, but Brexit Secretary Stephen Barclay said plans were being made for that to happen because “it’s better to have it and to not need it, than to need it and not have it”.

But Commons Speaker John Bercow has insisted that there would have to be substantial changes before he would allow another vote on an issue that had already been considered.

Will She Get Enough Support For Her Deal This Time Around?

Lead Brexiteer Boris Johnson, who once compared May’s deal to a “suicide vest” wrapped around the British constitution, told the European Research Group of Tory MPs he will now back it.

Other Eurosceptics previously opposed to the deal have also reluctantly swung behind it because they fear the alternatives are now softer forms of Brexit or the possibility of not leaving the EU at all. 

But the Democratic Unionist Party remain opposed, with leader Arlene Foster saying she could not sign up to a deal that “threatens the union” of the United Kingdom.

The DUP’s continued opposition means that some Tories, including Jacob Rees-Mogg, will also refuse to back the deal.

May’s pledge to quit could also put off any Labour MPs considering voting in favour. They worry that May’s replacement could be an even more hardline Brexiteer than her.

What Is The Prime Minister Saying About Her Deal?

May told MPs: “I know there is a desire for a new approach – and new leadership – in the second phase of the Brexit negotiations – and I won’t stand in the way of that.”

But in order to get to that “second phase”, her deal would have to pass. It remains to be seen whether her commitment to leave office is enough to win over wavering rebels.

Rees-Mogg acknowledged that if her deal did not get through then “she would have every right to carry on”.

But a third defeat – or ducking another vote entirely – would surely cause further damage to her crumbling authority.


So When Will May Leave No. 10?

Once the Withdrawal Agreement is passed, the government needs to rush an implementation bill through parliament, along with other legislation needed to ensure a smooth departure.

It is unclear whether the prime minister would delay her resignation until this process is complete and the UK formally leaves on May 22.

It would be possible for her to declare she is stepping down, but to remain in post during the contest to select a successor. 

If she remains in office until May 25, she will overtake Gordon Brown’s tenure of two years and 319 days in office to become the 35th longest-serving PM in British history.

If she lasts until May 26, she outstrips the Duke of Wellington and another 28 days to June 23 will take her past Neville Chamberlain.

She is due to represent the UK at the annual G20 summit in Osaka, Japan, on June 28-29, which could be her last outing on the international stage before stepping down.

(Infographic supplied by Statista)