The EU's Brexit negotiators have told European governments that Theresa May must guarantee there will be no hard border between Northern Ireland and the Republic of Ireland under any circumstances, and regardless of the final outcome of the withdrawal negotiations, BuzzFeed News has learned.
In an update prepared by chief EU negotiator Michel Barnier's team – the contents of which have been shared with BuzzFeed News – the governments of the remaining 27 states have been told that Monday's working lunch in Brussels between the British prime minister and EU Commission president Jean-Claude Juncker will be a "make or break" moment for phase one of the negotiations.
The Irish border question remains the most complicated issue yet to be resolved. Senior European government officials told BuzzFeed News that the briefing from the European Commission makes clear that May will need to keep the door open for Northern Ireland continuing to effectively be part of the single market and the customs union in the worst-case scenario of no other feasible solution being found, or if talks were to fail.
The feeling in Brussels is that May has yet to sell this point back home.
But such a guarantee would put the prime minister in grave danger of losing the support of Northern Ireland's Democratic Unionist Party, on whose votes she relies to prop up her minority government in the House of Commons, as it would raise the possibility of border checks for people and goods travelling between Northern Ireland and mainland UK.
Despite positive signs in recent days, gaps between the two sides persist. Barnier's team have told EU governments that there are also sticking points on sovereignty and citizens' rights.
Although EU nationals in the UK sending benefits abroad will be able to continue to do so, an agreement on exporting family benefits in future is still pending, and there are also details to iron out on winter fuel allowance payments for the elderly.
The EU27 capitals have been told that an agreement has been reached on family reunion rights, including on children who will be born to EU nationals after Brexit. And BuzzFeed News understands that the EU is prepared to make at least one concession by accepting that the right of spouses to move to the UK in future will be covered by terms set out in UK law.
Crucially, negotiations remain open on the extent of the role the European Court of Justice (ECJ) will have in protecting citizens' rights after the UK leaves the EU in March 2019.
Brussels has reaffirmed to the 27 leaders that the issue is seen as a critical matter of sovereignty for the UK, and Britain wants to clearly limit the role of the ECJ after Brexit in both scope and time. Ending the jurisdiction of the ECJ in the UK is one of May's red lines.
But the EU does not want to see the ECJ's role limited to providing advice to the UK Supreme Court, and wants any limit to extend to 10 years from any first case that is brought to the courts as by then any pending cases would have concluded.
One issue where a deal is within reach is the so-called Brexit divorce bill. EU leaders have been told that an agreement on settling the UK's financial commitments has been "basically agreed" after the UK provided "a clear commitment" on both "budget and off-budget items".
"It's mostly an issue of presentation now," a senior official said.
The breakthrough in the debate over the divorce bill was first reported on Wednesday by the Telegraph and the Financial Times. The final figure that the UK will pay over several years is understood to be around £45-55 billion – an amount that the British government denied for months would be the bill's landing point.
Any suggestion that Northern Ireland could get a special carve out from the rest of the UK's post-Brexit status is likely to cause tensions between the government and the DUP.
Earlier this week the DUP threatened to pull its support for May's government if Northern Ireland was treated as a separate customs and trading regime from the rest of the UK after Brexit.
And speaking in Dublin on Friday, Irish taoiseach Leo Varadkar said: “On the question of the border, as I have said many times, the best and most obvious solution would be for the UK to remain in the customs union and the single market. But if the British government continue to rule out that option it must offer credible, concrete and workable solutions that guarantee there will be no hard border, whatever the outcome in the negotiations, and whatever the future relationship between the EU and the UK."
Speaking at the taoiseach's side, the president of the European Council Donald Tusk said he had come to Dublin to reassure the Irish people that the EU was fully behind the request for no hard border. Tusk said: "The Irish request is the EU’s request."
Tusk added: “Let me say very clearly: If the UK's offer is unacceptable for Ireland, it will also be unacceptable for the EU. I realise that for some British politicians this may be hard to understand. But such is the logic behind the fact that Ireland is an EU member while the UK is leaving. This is why the key to the UK’s future lies – in some ways – in Dublin, at least as long as Brexit negotiations continue."
The EU's 27 leaders will meet in Brussels on 15 December to decide whether there has been the "sufficient progress" needed to move the negotiations on to discussions about transitional arrangements, and the future UK-EU trade relationship.
Alberto Nardelli is Europe editor for BuzzFeed News and is based in London.
Contact Alberto Nardelli at email@example.com.
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