THERE will be no Brexit deal between the UK and European Union without a "backstop" option on the Irish border, the EU's chief negotiator has warned.
Michel Barnier said it was "an EU issue, not only an Irish issue" and agreement was needed "rapidly" by June before a final crunch summit in October.
He also rejected criticism yesterday from DUP leader Arlene Foster, who claimed the EU had "become very aggressive" and accused him of not understanding unionist culture.
The British government has accepted in principle the need for a backstop to be written into the Brexit withdrawal agreement.
This would effectively see the north remain within the EU single market and customs union if no other solution is found.
But many operational details have yet to be resolved, and the UK is still pushing for a different border arrangement to be agreed.
British prime minister Theresa May said in February that EU proposals on Northern Ireland would "threaten the constitutional integrity of the UK" and "no UK prime minister could ever agree to it".
Speaking yesterday at an all-island Brexit forum in Dundalk, Co Louth, Mr Barnier said he knows the backstop has been the subject of "heated discussions in the UK".
"To be clear: without a backstop, there can be no withdrawal agreement. This is an EU issue, not only an Irish issue," he said.
"I can assure you that Ireland has the full support of all member states and all EU institutions."
He added: "We have no intention of questioning the UK's constitutional order. That is none of our business.
"We are seeking practical - practical and operational - solutions to a complex problem. No more, no less."
Mr Barnier said the backstop "is not there to change the UK's red lines", but is included "because of the UK's red lines".
"The UK's decision to leave the single market and the customs union creates a risk that the hard border will return. This is why it is necessary to have a self-standing backstop solution," he said.
Earlier, in a BBC interview, Mrs Foster claimed Mr Barnier does not "understand the wider unionist culture of Northern Ireland".
"He's hearing a very strong message from the Republic of Ireland's government, he's hearing it from Sinn Féin," she said.
"We have tried to get him to understand the unionist position for the people of Northern Ireland, but he hasn't really responded to that and I'm disappointed about that."
In response, Mr Barnier said: "There is no spirit of revenge.
"I personally regret Brexit for many reasons and I am never aggressive.
"My door is open."
On Brexit talks, Mr Barnier added: "We need to agree rapidly by June on the scope of all-island customs and regulations, the safety and controls that we need to respect the single market."
This summer's meeting of European leaders in Brussels would be a "stepping stone" for the final summit in October, which is the deadline for reaching an agreement on withdrawal, he added.
His keynote speech in Dundalk was part of a two-day visit to Ireland – his third visit as the EU's chief Brexit negotiator.
After delivering his speech, Mr Barnier crossed the border to Newry in Co Down for meetings with business leaders.
Today he will visit Derry to meet with business stakeholders and cross-border groups, before travelling to Dungannon in Co Tyrone to meet rural representatives.
