“The draft legal text the Commission have published would, if implemented, undermine the UK common market and threaten the constitutional integrity of the UK by creating a customs and regulatory border down the Irish Sea, and no UK prime minster could ever agree to it,” May said Wednesday at the weekly Prime Minister Question session in the British House of Commons.
May declared she will be making it clear to EU officials that her government will never sign up to the document: “I will be making it crystal clear to President Juncker and others that we will never do so.”
The EU's draft withdrawal agreement includes a proposal to effectively keep Northern Ireland inside the bloc's single market and customs union in order to ensure there will be no hard border with Ireland, an EU member state.
The EU draft plan would only come into effect if no other solution to the border issue is found.
British Prime Minister Theresa May has ruled out any customs union deal with the EU after Brexit, arguing that it would keep London from striking new trade deals with fast-growing economies like China and India.
However, she has been struggling to unite her cabinet and offer a clear path to the divorce by its October deadline. She is also facing a rebellion by a small group of pro-Europeans inside the ruling Conservative Party, while on the other side, over 60 Conservative lawmakers have called on her to quickly break from the European Union, urging her to take a “hard Brexit” stance.
Supporters of Brexit think the ability to strike new trade deals around the world is one of the big potential gains of leaving the EU.
On the other hand, staying in a customs union allows the UK to avoid paying tariffs for its exports to the bloc while curbing the risk of a return to a “hard border” between Northern Ireland and the Republic of Ireland, an issue that has hurdled talks with the EU.
Northern Ireland debacle
Northern Ireland will be the only part of the UK to share a land border with an EU member state after the UK leaves the EU.
London wants to withdraw from the customs union — within which goods can move freely — but has said it will not reimpose border posts, which many have said might upset the last 20 years of peace in Northern Ireland.
A hard border would make passport and customs controls mandatory, hampering business ties between the Republic of Ireland and Northern Ireland.
The EU is concerned that the adoption by Northern Ireland of different regulations on issues like food safety, environmental health and workers' rights would make border checks necessary, in order to prevent goods that do not meet EU standards from being brought into the bloc, potentially undercutting European rivals.
EU member states are also increasingly frustrated with Britain’s reluctance to compromise, and are also worried that May's fragile Conservative government is unable to do so even if it wanted to.