28/02/2018 11:51 GMT | Updated 28/02/2018 13:46 GMT

Theresa May Rejects EU Plan To Keep Northern Ireland In The Customs Union

Brussels accused of trying to 'annex' part of the UK.

Theresa May has flatly rejected the European Union’s plan to keep Northern Ireland inside the customs union.

The prime minister told the House of Commons on Wednesday afternoon that “no UK prime minister could ever agree” to the draft legal text published by Brussels.

Speaking during prime minister’s questions, May said it would “undermine the UK common market and threaten the constitutional integrity of the UK”.

The EU earlier revealed its Brexit proposals. Included in the 120-page document is a proposal to avoid a hard border between Northern Ireland and the Republic of Ireland by creating a “common regulatory area”.

This would effectively keep Northern Ireland inside the customs union and single market.

But it would also create a customs border in the Irish Sea between Northern Ireland and the rest of the UK.

Michel Barnier, the EU’s chief Brexit negotiator, said the “backstop” plan was needed to protect the Good Friday Agreement designed to stop a return to violence.

Speaking in Brussels moments before PMQs, Barnier said UK had yet to put forward its own plan.

“We have applied imagination and creativity to find a specific solution to the unique challenge that Brexit poses,” he said.

Arlene Foster, the leader of the DUP, said the proposed draft text from Brussels was “unacceptable”.

Without the DUP’s support, May does not have a majority in the Commons.

Boris Johnson this morning said the issue of the Northern Ireland border was being used by pro-Remain campaigners to try and keep the whole of the UK in the customs union “so we cannot really leave the EU”.

DUP MP Ian Paisley said the prime minister had to “show some teeth” and reject the EU’s plan.

“I’m appalled and disgusted at how the EU can dare to say that they want to annex a part of the United Kingdom,” he told the Commons Northern Ireland committee.

Pro-Brexit Labour MP Kate Hoey told Sky News: “We cannot have Northern Ireland treated any different than any other part of the UK.”

David Jones, a former Brexit minister, told BBC Radio 4′s Today programme the EU’s plan was “unacceptable”.

“What is proposed is that we should remain, that Northern Ireland should remain part of the customs union, it should effectively be part of the single market and should, I understand, remain subject to the jurisdiction of the European Court of Justice and that effectively amounts to an annexure of Northern Ireland by the EU,” he said.

The British Government has set out three ways to avoid a hard border – resolving the issue as part of a new trade relationship with the EU, specific technological solutions to the issue or – as a fallback option – regulatory alignment with EU rules to protect economic co-operation and the Good Friday Agreement.

But a memo sent by Johnson to May and other members of the Brexit war cabinet appeared to suggest a hard border remained a possibility, and would not be as damaging as feared.

The document, obtained by Sky News, said “it is wrong to see the task as maintaining ‘no border’” on the island of Ireland and the government’s aim will be to “stop this border becoming significantly harder”.