The House of Commons will consider the Bill this afternoon, along with changes to it which would guarantee in law the rights of EU citizens to live and work in the UK after Brexit and of Parliament to have a vote on any deal Ms May brings forward.
The Prime Minister hopes to see the Bill pass unamended, but a handful of Tory rebels are demanding further verbal assurances that Parliament will have a greater role in determining the country’s future.
Among those asking for concessions are ex-education secretary Nicky Morgan, who said a vote on the endgame was “not about making sure that Brexit doesn’t happen” and warned Ms May she would face Tory disunity unless she gives in to the demands.
She told the BBC Radio 4’s Today programme: “I think if the Prime Minister wants a united party then this is a simple reassurance that can be given by ministers at the dispatch box that will have the effect, as I say, of my and my colleagues supporting the Government in this.”
The House of Lords approved two amendments to Ms May’s Bill, on EU citizens and on giving Parliament a ‘meaningful vote’ on the final Brexit deal.
But despite some unrest on Tory benches, MPs and peers are likely to give the green light to the unamended legislation today, clearing the way for Ms May to trigger Article 50 as early as tomorrow.
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Former Labour chancellor Alistair Darling said peers should back down if their amendments are overturned by MPs, but also backed Ms Morgan’s stance on a meaningful vote.
The peer told Today: “The job of the Lords is to ask the Commons to think again. The Commons has got to be supreme.
“I was 27 years a member of the House of Commons, I feel very strongly about that, the Lords is there to revise but at the end of the day the House of Commons is a democratically elected body.
“I don’t want Brexit, I think it’s bad, I think we’ll regret it, but that’s the way it is.”
On Tuesday the Prime Minister is to give a statement in the Commons on last week’s summit of the European Council, providing an opportunity to make the announcement.
She has previously promised to trigger Article 50 of the Lisbon Treaty, officially launching a two-year countdown during which time talks on the UK’s future relations with the EU must be concluded or the country drops out with no deal.
Brexit Secretary David Davis has said that if Parliament tries to amend the Article 50 bill, it would hamper Ms May in negotiations with EU countries and suggested the amendments are actually more about Remainers attempting to stop the UK quitting the bloc altogether.
He said: “Please don’t tie the Prime Minister’s hands in the process of doing that for things which we expect to attain anyway.
“What we can’t have is either House of Parliament reversing the decision of the British people.”