Unionist and nationalist politicians in Northern Ireland offered polarised responses to the European Union's draft proposal for a post-Brexit "common regulatory area" on the island of Ireland.
While DUP MPs made the party's position clear to British prime minister Theresa May in the House of Commons, party leader Arlene Foster was equally adamant that the proposal was "constitutionally unacceptable" and potentially "catastrophic" for Northern Ireland.
Ms Foster welcomed Ms May’s commitment that the British government would not permit a border in the Irish Sea.
“Northern Ireland must have unfettered access to GB market,” Ms Foster said.
However, Sinn Féin's Northern leader Michelle O'Neill countered that "any objective analysis will demonstrate that leaving the Customs Union is "incompatible with avoiding a border in Ireland".
She described the “outright rejection” of the EU plan by both the British government and the DUP as an “appalling display of arrogance”.
“The Tories and DUP have no right to hold 27 EU nations to ransom. They have no right to play fast and loose with an internationally-binding treaty such as the Good Friday Agreement,” said Ms O’Neill.
She added: “It is also completely erroneous for Theresa May to claim no British prime minister could agree to a proposal which she claims undermines her country’s ‘constitutional integrity’, when she herself agreed to it in December before her infamous phone call from Arlene Foster.”
SDLP Brexit spokeswoman Claire Hanna said that what Brussels chief negotiator Michel Barnier had tabled was "essentially what was agreed by the UK and the EU in December".
“While I know many will feel the need to go kicking and screaming over the contents of this document, but to those Brexiteers I say, it’s time they faced up to reality. It’s time for calm heads and for hard choices,” she said.
“The UK government and the Brexiteers have a choice, they either go for alignment with the customs union and the single market to protect these islands – or they support the EU on the common regulatory area. It is just fantastical to pretend that there’s some other mystery option – there isn’t,” added Ms Hanna.
Ulster Unionist Party MEP Jim Nicholson welcomed Ms May's rejection and said the proposal would have "devastating implications for the constitutional integrity" of the United Kingdom.
"The proposals published today by Michel Barnier show a tremendous level of ignorance of the Belfast Agreement, a disregard for the principle of consent and disrespect towards the constitution of the United Kingdom," said Mr Nicholson on Wednesday.
“It is a clear departure from the text agreed in December. These proposals are tantamount to annexing Northern Ireland economically and politically away from the rest of the United Kingdom,” he added.
“The fact remains all sides need a sensible deal that works for all parties. We need to proceed with cool heads,” said Mr Nicholson.
Traditional Unionist Voice leader Jim Allister said the "EU's attempt to annex Northern Ireland needs actions, not words" from Ms May.
“The audacity of Brussels in demanding a border down the Irish Sea is staggering for anyone unfamiliar with the Machiavellian processes of the EU,” he said. “It is driven, of course, not just by their malevolent attempt to derail Brexit but by a desperation to avoid its treaty obligations to protect and man EU customs borders – hence, the ploy to push its border back to Larne.”
Mr Allister said what Ms May “foolishly agreed in December 2017 opened the door to this EU belief that it could annex Northern Ireland from being a province of the UK to being a province of the EU”.