Boris Johnson faces the first massive tests of his Brexit deal today as Remainer MPs try to kill the legislation in crunch votes.
The Prime Minister has fired the starting gun on a 72-hour dash to get crucial legislation implementing the package through - urging the House of Commons to 'take back control' from Brussels.
But MPs have voiced fury at 'appalling' efforts to rush the laws through Parliament in just three days, and the government is desperately struggling to fend off amendments that would keep the UK in the EU's customs union or force a referendum.
Critically for Mr Johnson, former Tory rebels including Rory Stewart and Ken Clarke have indicated they could go against the government.
Downing Street has been increasingly optimistic that the numbers are in place to win the first big vote on the legislation tonight, known as the second reading. There are claims that Labour could abstain, although sources were playing the idea down this morning.
However, there are mounting fears that MPs will use the 'Titanic Tuesday' showdown to take an axe to the PM's plans to push the measures through at breakneck speed.
Defeat of the so-callled programme motion - which sets out a tight schedule for passing the EU Withdrawal Bill - is essential for Mr Johnson to keep his 'do or die' vow to secure Brexit by October 31.
Boris Johnson has published his 110-page Brexit Withdrawal Bill just hours before MPs will debate it amid Commons anger that it is being rushed through (pictured: Prime Minister Boris Johnson arrives at The Houses of Parliament on Friday)
The WAB runs to 110 pages and is accompanied by 124 pages of explanatory notes
But Remainer MPs hope that if they drag their heels the EU will agree to delay the date for months.
A spokesman for the PM would not comment on whether he would pull the Bill if a customs union was added, although No10 suggested yesterday that the process will be at risk.
Tuesday: Potentially the most critical day for the Brexit deal. Debate on the WA legislation will begin in the Commons, with crucial second reading votes expected in the evening.
If the Bill is torpedoed at this point, the Brexit process will be back to square one.
The programme motion will also need to be approved, setting out the timetable for legislation being passed, if Mr Johnson is to have much chance of getting Brexit through for October 31.
Wednesday-Thursday: Assuming the second reading is successful, detailed scrutiny will be carried out in the Commons and the Lords.
There could be votes on amendments calling for customs union membership and a second referendum.
All being well, final approval should be given at third reading on Thursday night.
Friday-Sunday: The Bill moves to the Lords where another fight for surpremacy beckons between the government and Remainers.
October 28: The EU has suggested an emergency summit could be held on this date to consider a Brexit extension if the deal has not gone through Parliament.
Overnight Mr Johnson appealed to MPs to back his deal 'so that we can leave without disruption and provide a framework for a new relationship based on free trade and friendly co-operation'.
The PM said: 'I hope Parliament votes to take back control for itself and the British people and the country can start to focus on the cost of living, the NHS, and conserving our environment.
'The public doesn't want any more delays, neither do other European leaders and neither do I. Let's get Brexit done on October 31 and move on.'
Government sources said there was a 'good chance' the deal would pass its first Commons hurdle today when MPs vote on whether they support it in principle.
But there is a growing revolt over Mr Johnson's plans to push the deal through quickly to meet his 'do or die' pledge to leave by