The British government faces another nerve-rattling test this week as its flagship Brexit legislation is picked over once again by a restive parliament.
Grieve's amendment has already won backing from the unelected House of Lords, setting up a vote in the elected Commons. The question is by how much?
The move comes after peers voted for a second time for an amendment to the EU (Withdrawal) Bill giving the Commons a "meaningful vote" on a final Brexit deal after it was rejected last week in the lower chamber.
"It has been suggested I want to collapse the government, I do not".More news: MultiChoice finds no racism involved in Ashwin Willemse walk-out
Mr Grieve said on Tuesday that he still hoped it would be possible to come to a "sensible compromise" that would address the concerns of both sides.
Lord Hailsham said: "The government's amendment not only fails to deliver the promised meaningful vote".
Among the Tory peers who voted against the government were senior figures such as Michael Heseltine, Chris Patten and Sayeeda Warsi.
Britain is due to leave the European Union on March 29, 2019, and the bloc is frustrated with what it sees as a lack of firm proposals from the United Kingdom about future relations.
Mr Grieve said: "What I said, which was rather typically misinterpreted by some sections of the press, was - would not rejecting a deal potentially lead to the collapse of the government - and I said yes".More news: U.S. rapper XXXTentacion shot dead in Florida
"We can not let Parliament tie the Government's hands", she said at an event in Omagh, Co Tyrone.
The amendment approved in the House of Lords yesterday was based on an agreement that Grieve said he had reached in talks with Solicitor General Robert Buckland last Thursday, only for ministers to introduce changes at the last minute which Grieve said were "unacceptable".
Last week, the prime minister avoided defeat on the issue - but the would-be rebels said they were not happy with the concessions they were subsequently offered in return for not voting against the government.
He told MPs the timing of the debate was apt because at the other end of Parliament, the Lords were now exercising "an incredible amount of influence and power over the European Union (Withdrawal) Bill", as they debated amendments rejected by the House of Lords.
Alongside the number of Tory rebels, the chances of the amendment being passed in the House of Commons will also depend on how solid support is from the opposition Labour Party.More news: Trump threatens additional tariffs on $200 billion of Chinese goods
She said part of the?20 billion ($27 billion, 23 billion euros) injection would be funded by "the money we no longer spend on our annual membership subscription to the European Union".