Brexit secretary David Davis has made a last-ditch attempt to persuade would-be Tory rebels not to vote against the government on today's amendments, saying the EU referendum result was irreversible.
The Commons will this afternoon start a two-day debate on whether to accept the 15 amendments to the EU Withdrawal Bill which were passed by the House of Lords.
Theresa May last night brokered a fragile unity among MPs, pressing the case that Brussels will be watching and urging them not to undermine negotiations. However one amendment - Dominic Grieve's call for a meaningful vote - is looking increasingly well-supported, not least by Phillip Lee, the former youth justice minister who resigned this morning over the government's handling of Brexit.
However Davis urged his backbench colleagues to fall in with the party, telling the BBC's Today programme Grieve's amendment would not give "the ability to reverse the decision of the referendum".
“Whatever we do, we’re not going to reverse that,” he said.
Asked what would happen if MPs rejected the deal, he said there would be no time to restart negotiations, with the UK leaving the EU in March 2019.
"If they throw it out, well they throw it out," he said.
The government is sticking by its amendment - a commitment by ministers to make a statement within 28 days if MPs vote down the final deal.
A Number 10 spokesman said this afternoon: "We have put down our own amendment and that's the amendment we are going to be supporting".