MPs must have a vote if the Government chooses to breach the terms of the Withdrawal Agreement, a senior Tory MP has said.
The Government has accepted the calls of Sir Bob Neill, the Tory chairman of the Commons Justice Committee, to offer a "parliamentary lock" in the event of a potential deviation from international law.
Sir Bob said ministers would have to make a "persuasive" case to MPs that the EU was acting in "breach of their obligation of good faith" in order for them to vote for such a move.
During the third day of committee stage debate on the Bill, he told the Commons: "That's why I'm prepared to adopt the formulation of the Lord Chancellor that such a thing might be acceptable in extremis.
"This is not a carte blanche for the Government - and in fairness I don't think ministers have ever taken it as such and I think they know that it weighs heavily to do such a thing.
"So that's why if the Government moves amendment 66 tomorrow when we get to that stage, I will be prepared to withdraw my amendment but it is to give the Government the chance to make its case as to why such an exceptional step should be necessary."
He added: "This has not been the most edifying of spectacles for the House of Commons over the last few days but I hope it's one where we can at the end of the day find a constructive way forward.
"I say it's not edifying because much of the purpose of the Bill is important and valuable but to act in contemplation of something which most of us would regard as unworthy - namely to breach an international obligation - is not something that one should ever seek to discuss lightly."
Liberal Democrat former cabinet minister Alistair Carmichael said the threat of the removal of the whip could make any parliamentary vote easy for the Government to win.
He added: "Just last week Number 10 Downing Street was briefing out that he and those who agreed with him would have the whip removed if they followed through on it. Now that is the pressure that members on that side of the House will be put under.
"Can I put to him that it is possible that the Government has accepted his proposition because they see it as something that in practice will not cause them any difficulty."