The latest EU position defended at Brexit negotiations this week is that avoiding a hard border between the Republic and Northern Ireland requires "ensuring no emergence of regulatory divergence from those rules of the internal market and the customs union".

This is because "an important part of political, economic, security, societal and agricultural activity on the island of Ireland currently operates on a cross-border basis, underpinned by the joint EU membership of the UK and Ireland".

In practice, ensuring no "regulatory divergence" means that Northern Ireland would continue to apply the rules of the EU's single market and customs union, effectively remaining part of these structures.

The UK's Brexit secretary David Davies rejected the idea at the end of this week's round of negotiations. "We respect the European Union desire to protect the legal order of the single market and Customs Union. But that cannot come at cost to the constitutional and economic integrity of the United Kingdom," he said in Brussels this Friday. "This cannot amount to creating a new border inside our United Kingdom."

The EU's position is also unlikely to find favour among Unionist politicians, as illustrated by the reaction of UUP MEP Jim Nicholson:

Article 50 can be reversed – diplomat

Meanwhile, former UK ambassador to the EU Lord Kerr argues that the UK can still row back on Brexit "at any point in the process". Despite Prime Minister Theresa May triggering Article 50 of the European treaty on formally leaving the Union, Lord Kerr said that there were no legal provisions against a reversal of that decision until Brexit was fully effective. "We don't have to go if at any stage, within the two years, we decide we don't want to," he said.

In a speech to be delivered this Friday and published by the campaign group Open Britain, the veteran diplomat quoted An Taoiseach Lea Varadkar as saying: "The door remains open for the UK to stay in the EU." Lord Kerr added: "As new facts emerge, people are entitled to take a different view. And there's nothing in Article 50 to stop them."

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