Theresa May’s Brexit plans are due to be put to the Commons this week following a five-day debate in Westminster.
The vote had been scheduled to take place in December but was called off at the 11th hour with Government victory looking unlikely.
The moment Theresa May delayed the vote on her Brexit deal
MPs continue to be divided on the plans, with a number of pro-Remainers calling for Mrs May’s deal to be voted down, and some ardent Leavers pushing for the same result to ensure a no-deal Brexit.
Here’s a look at what could happen following Tuesday’s vote.
The Government wins the vote
The simplest outcome to plot comes if the Government wins the vote on the Withdrawal Agreement.
In this instance, the UK would leave the European Union on March 29 under the terms of Theresa May's Brexit deal.
However if MPs reject May's deal, a whole host of scenarios could play out.
Three former prime ministers, a number of former ministers and a sizable number of opposition MPs have called for a so-called People's Vote to break the impasse.
Theresa May is strongly against the idea, and campaigners for a second referendum are not yet agreed on what the question would be.
Should the EU not agree to a postponing of Brexit then the UK would leave the EU without a deal on March 29.
This is the preferred option of a number of Tory Brexiter MPs, which would see the UK leave the EU under World Trade Organisation terms - and with no broad agreement in place with the EU.
Downing Street has dismissed this option, arguing the EU has made it clear that it will not discuss no-deal deals until the UK has actually left the EU.
Extension to Article 50
The Government could also ask for an extension to Article 50 – which would have to be agreed by the remaining 27 members of the bloc.
The big unknown is if the EU agrees to an extension of Article 50 and there is the potential for negotiations to be reopened.
This Plan B could include discussion about a free trade agreement, customs union, membership of the single market and even a second referendum on the deal.
The prospect of Labour putting forward a vote of no confidence in Mrs May has been mooted and a general election could take place should the Government lose.
Any potential incoming Prime Minister could also agree that the UK would be best served by trading on World Trade Organisation terms.