Justice minister Dr Phillip Lee MP quit the government today to allow him to campaign for MPs to be allowed a vote on the European Union withdrawal deal.
The "meaningful vote" will be the first major test after the House of Lords introduced 15 changes to the bill, trying to reshape the government's approach to Brexit by encouraging lawmakers to press for the closest possible ties.
Justice Minister Philip Lee resigns and pledges to vote against Theresa May on Brexit.
It followed a meeting of the backbench 1922 committee this evening ahead of a series of crunch Commons votes in which Mrs May told MPs to consider the signal that would be sent to Brussels if the government was defeated.
One of the key points of difference between the Prime Minister and the rebels is a Lords amendment which states the Government must seek to negotiate a customs union with the EU.
"But the message we send to the country through our votes this week is important".
"But if the Lords amendments are allowed to stand, that negotiating position will be undermined".More news: Mom wanted me to do a film like 'Sairat': Janhvi
"The goal of the EU Withdrawal Bill is simple - it is putting EU legislation into law to ensure a smooth and orderly transition as we leave", she is expected to tell them.
"Whatever we do, we're not going to reverse that", Davis told BBC radio.
The government has also tried to stem rebellions by offering its own options - on the "meaningful vote", it has proposed a 28-day breathing space if parliament rejects a Brexit deal.
There are two amendments that could prove particularly tough for the government to overturn.
"We are asking members of parliament to abide by the referendum result, our manifesto commitment and to back our country", Andrew Bridgen, Conservative lawmaker and Brexit campaigner, told Reuters.
The speech will come on the eve of two days of debates and voting on amendments to the EU Withdrawal Bill, which is scheduled to last 12 hours. She now relies on the support of a small Northern Irish party.
It is expected that Tuesday will see MPs decide whether Parliament should have the power to set the Government's negotiating goals if Theresa May's deal with Brussels is voted down. "And I imagine that there will be (more)".