Ministers will again battle to win over MPs to Theresa May’s Brexit deal later, a day after the government suffered three defeats on key votes.
Security will be the focus of the second of five days of debate in the Commons, where Tuesday’s marathon session extended into the early hours.
Crucially, MPs backed calls to give them a direct say in what happens if Mrs May’s deal is rejected next week.
A former Tory chief whip has told the BBC he expects the PM to lose the vote.
Mark Harper, who backed Remain in the referendum, said he would vote against the withdrawal agreement, and predicted the deal would be rejected by 80 of his party colleagues.
The deal has been endorsed by EU leaders but must also be backed by the UK Parliament if it is to come into force. MPs will decide whether to reject or accept it next Tuesday, 11 December.
However, Mr Harper urged the prime minister to renegotiate the deal, insisting the current plan would leave the UK worse off.
Ministers will plough on with attempts to win over MPs on Wednesday, with eight hours of debate on the security and immigration aspects of the withdrawal agreement.
Meanwhile, Mrs May is expected to continue trying to convince small groups of her MPs to back the plan in private meetings.
“I promise you today that this is the very best deal for the British people and I ask you to back it in the best interest of our constituents and our country,” she told the Commons on Tuesday.
The PM spoke after a torrid afternoon which saw her government ruled in contempt of Parliament for failing to comply with a binding vote demanding the publication in full of legal advice it had received before agreeing the Brexit deal.
Why did the defeats matter?
First, the government lost a bid to have the legal advice issue dealt with separately by a the Privileges Committee of MPs.
In a second defeat, ministers were forced to concede they would have to publish that advice in full, having previously argued this would break convention and was not in the national interest.
Most significantly, the third defeat was over changes to the parliamentary process in the event the Commons voted down Mrs May’s deal.
Instead of being confined to merely taking note of what the government tells them, MPs would also be able to exert more influence by voting on what they wanted the government to do.
This could potentially see Parliament wrest control of the Brexit process from ministers if, as expected, MPs push for a “Plan B” alternative to Mrs May’s deal and seek to prevent any chance of Britain leaving the EU without a deal in place.
Former Attorney General Dominic Grieve, who brought the motion, told Channel 4 News it would “allow the UK time to consider its options”, including re-starting negotiations with the EU or giving the public the final say.
Liberal Democrat leader Sir Vince Cable said: “The Commons is now very likely to defeat the government again next week on the Brexit deal, at which point the country must be given a ‘People’s Vote’, and asked to choose between the deal or remaining in the EU.”