Speaker John Bercow announced the two amendments for consideration at the start of the Commons today.
The first is the amendment from Independent Sir Oliver Letwin, the former Cabinet minister who had the Tory whip withdrawn after rebelling over Brexit, which proposes to withhold approval for the deal unless and until legislation implementing it is passed.
The second for MPs to consider will be a cross-party amendment rejecting a no-deal Brexit and seeking a second referendum.
Sir Oliver’s proposal states that the House “withholds approval” of the deal until such time that the legislation to enact the deal has been passed.
The reason for this is that a straightforward approval would prevent the Benn Act – which obliges the PM to request an Article 50 extension if he does not have an approved deal – from kicking in.
The Letwin amendment means Mr Johnson would be forced to apply for an extension regardless of the result.
This is voted on first and has the backing of Labour and the Tory rebels, so could pass.
Unless Mr Johnson finds a way to ignore it, he may be in the embarrassing position of having to ask for a Brexit delay beyond October 31.
Sir Oliver said it was an “insurance policy” to prevent Britain “crashing out” without a deal on Oxford.
But Government sources reportedly warned that if it passed, Tory MPs will essentially abstain on the final vote and the Withdrawal Agreement Bill will be introduced next week.
A Number 10 source confirmed that Sir Oliver was in Downing Street for talks on Friday.
The second amendment is from MP Peter Kyle, who represents Hove and Portslade.
It rejects leaving the EU without a deal and states that the final decision on the future relationship between the UK and the EU should be subject to a referendum.
Hundreds of thousands of people are expected to descend on London today for the People’s Vote march , which demands a second referendum.