British Prime Minister Theresa May faces a showdown in parliament on Tuesday with lawmakers who want more power to challenge an eventual Brexit deal, testing both her authority and her plans for leaving the European Union.
On the first day of votes that could further complicate her tortured negotiations to quit the EU, parliament will debate a demand for a "meaningful vote" on any agreement May negotiates with Brussels before leaving the bloc next March. Such a vote would give the lower house more power to set the government's "direction" if the house rejects the agreement.
It will be the first major test after the upper house, the House of Lords, introduced 15 major changes to her Brexit blueprint, the EU Withdrawal Bill, including that on the "meaningful vote." Underlining the fear that some of her Conservatives could vote against the government, May addressed her own lawmakers at a meeting of its 1922 Committee in a last-ditch appeal for them to unite around her plans to leave the EU.
"If the Lords amendments are allowed to stand, that negotiating position will be undermined," she told them, adding that she was confident that "I can get a deal that allows us to strike our own trade deals while having a border with the EU which is as frictionless as possible." Her appeal was cheered and applauded.
Parliament will also debate other amendments handed down by the House of Lords, including a challenge to the government's plan to put March 29, 2019, or 'Brexit Day', into law and an attempt to toughen a commitment to ensure a frictionless border between Northern Ireland and the neighboring Irish Republic, which will remain in the EU.
On Wednesday, parliament will also consider a challenge to her commitment to leave the EU's single market and customs union, which will transform Britain's future trading relationships for many years to come.