Ruth Davidson has demanded Theresa May expand any special Brexit deal negotiated for Northern Ireland to the whole of the United Kingdom.
The Scottish Tory leader said if “regulatory alignment” between Northern Ireland and the Republic of Ireland was restricted to the island of Ireland it could risk damaging the “integrity” of the UK.
“The question on the Brexit ballot paper asked voters whether the UK should stay or leave the European Union - it did not ask if the country should be divided by different deals for different home nations,” she said.
“While I recognise the complexity of the current negotiations, no government of the Conservative and Unionist Party should countenance any deal that compromises the political, economic or constitutional integrity of the United Kingdom.
“All sides agree there should be no return to the borders of the past between Northern Ireland and the Republic of Ireland. Similarly, jeopardizing the UK’s own internal market is in no-one’s Interest.
“If regulatory alignment in a number of specific areas is the requirement for a frictionless border, then the Prime Minister should conclude this must be on a UK-wide basis.”
May’s hopes of striking a Brexit divorce deal with Brussels on Monday were scuppered after the Democratic Unionist Party (DUP) objected to her plan.
Crunch talks between the prime minister and European Commission president Jean-Claude Juncker ended in Brussels without a deal after the DUP – which props up the minority Conservative Government in Westminster – made clear it would not accept any arrangement which saw Northern Ireland treated differently from the rest of the UK.
The DUP, which has previously warned it could withdraw its support for Tories in Westminster if a deal is proposed which threatens the integrity of the UK by effectively establishing a customs border in the Irish Sea.
Speaking at Stormont, DUP leader Arlene Foster said: “We have been very clear. Northern Ireland must leave the EU on the same terms as the rest of the United Kingdom. We will not accept any form of regulatory divergence which separates Northern Ireland economically or politically from the rest of the United Kingdom.”
Her comments were swiftly followed by statements from the leaders of devolved administrations in Scotland, Wales and London, making clear that any special status for Northern Ireland would prompt demands from other parts of the UK for their own tailor-made Brexit.
But both May and Juncker said they were “confident” of reaching agreement in time for a key summit of the European Council on December 14, when it is hoped that leaders of the remaining 27 EU states will give the green light for the start of trade talks.