There is “no evidence to suggest that, right now, an invisible border is possible” between the North and the Republic after Brexit, a House of Commons committee has found.

In a report to be published on Friday, the Westminster Northern Ireland Affairs Committee calls on the British government to show how a “hard” border can be avoided should the UK leave the EU customs union and single market.

The committee, which conducted months of hearings and research on the subject, concluded that it had seen no evidence that this could be achieved.

“We have had no visibility of any technical solutions, anywhere in the world, beyond the aspirational, that would remove the need for physical infrastructure at the border,” the report says.

The committee’s membership includes Labour and Conservative MPs as well as three DUP MPs and Lady Sylvia Hermon, an Independent Unionist MP.

The committee’s report again highlights the gulf between the British government’s commitments to avoiding a hard border, and the lack of proposals as to how that might be achieved. This is also becoming a source of growing exasperation in Dublin and other EU capitals.

The report acknowledges that the joint report by the EU and the UK in December did not solve the border issue.

“This approach allowed the negotiations to move into the next stage but deferred, rather than solved, the central disagreement over how the UK’s decision to leave the single market and customs union will be reconciled with avoiding a hard border on the island of Ireland.”

Customs compliance

The report contains a number of recommendations that strongly urge Theresa May’s government to demonstrate how a hard border can be avoided.

“These proposals should provide detail about how customs compliance will be enforced if there is regulatory and tariff divergence between the UK and Ireland.”

The committee has heard months of evidence, including from border officials on the Swiss and Norwegian borders with the EU, in Dublin and in Northern Ireland, from British, Irish and EU officials and from EU chief negotiator Michel Barnier.

It also says that the British government’s intention to be outside the customs union and single market but require no border infrastructure is “unprecedented”.

The committee also says that it “very much regrets the continued absence of a functioning assembly and executive in Northern Ireland at this time of significant change for the whole of the UK”.