Dominic Raab resigned as Brexit secretary this morning, calling the UK's withdrawal agreement "a very real threat to the integrity of the United Kingdom".
Sterling plunged to 1.285 against the dollar in reaction to the news.
Raab, who helped negotiate the UK’s withdrawal agreement with Brussels, added that the Prime Minister’s proposed deal breaks promises the Tories made to the country at the last general election.
May’s deal would see the UK enter a temporary customs union with the EU in order to prevent a hard border between Northern Ireland and the Republic of Ireland.
The measure would stay in place until a permanent solution can be found, but Brexiters fear that this process could take years, and the EU has ruled out allowing the UK to quit the so-called backstop of its own accord.
Raab said: “I cannot support an indefinite backstop arrangement, where the EU holds a veto over our ability to exit.
“The terms of the backstop amount to a hybrid of the EU customs union and Single Market obligations. No democratic nation has ever signed up to be bound by such an extensive regime, imposed externally without any democratic control over the laws to be applied, nor the ability to decide to exit the arrangement.
“That arrangement is now also taken as the starting point for negotiating the Future Economic Partnership. If we accept that, it will severely prejudice the second phase of negotiations against the UK.”
Today, I have resigned as Brexit Secretary. I cannot in good conscience support the terms proposed for our deal with the EU. Here is my letter to the PM explaining my reasons, and my enduring respect for her. pic.twitter.com/tf5CUZnnUz— Dominic Raab (@DominicRaab) November 15, 2018
Sterling plunged on his resignation, falling to 1.285 against the dollar after reaching 1.305 after the Prime Minister secured cabinet support for her Brexit withdrawal agreement following a five-hour marathon meeting last night.
The pound initially fell to 1.297 against the dollar this morning after a Northern Ireland minister quit.
Shailesh Vara told May that her deal leaves the UK “in a half-way house with no time limit” on when it can fully leave the EU.
“This agreement does not provide for the United Kingdom being a soveriegn, independent country leaving the shackles of the EU, however it is worded,” he added.
“We are a proud nation and it is a sad day when we are reduced to obeying rules made by other countries who have shown that they do not have our best interests at heart.”
Meanwhile, European Council president Donald Tusk has called an emergency Brexit summit for 25 November, at which the 27 EU member states will vote on the draft withdrawal agreement.
“Let me say to our British friends: as much as I am sad to see you leave, I will do everything to make this farewell the least painful possible, both for you and for us,” Tusk said.
May’s agreement has come under fire from business figures and Brexiters, who claim it does not constitute a good deal for the UK.
The Prime Minister is set to face MPs later this morning but one Brexiter has told City A.M. they have put in a letter calling for a vote of no confidence in the Tory party leader.