Phil Hogan said the problems around the border — one of the key obstacles blocking talks on a UK-EU trade deal after the country leaves the bloc — could be solved by remaining in the customs union and single market, or allowing the North to do so.
His comments came after the Ms May’s DUP allies issued a warning that they would not tolerate attempts to put barriers between the North and the rest of the UK after Brexit.
The British prime minister has been given until December 4 to come up with further proposals on issues including the border, the Brexit divorce bill and citizens’ rights if European leaders are to give the green light to moving on to the next phase of negotiations covering the future relationship between the UK and Brussels.
Mr Hogan, the EU’s agriculture commissioner, said it was a “very simple fact” that “if the UK or Northern Ireland remained in the EU customs union, or better still the single market, there would be no border issue”.
In a swipe at the UK government’s approach to Brexit, he told yesterday’s Observer: “I continue to be amazed at the blind faith that some in London place in theoretical future free trade agreements.
“First, the best possible FTA [free trade agreement] with the EU will fall far short of being in the single market. This fact is simply not understood in the UK.
“Most real costs to cross-border business today are not tariffs — they are about standards, about customs procedures, about red tape.
“These are solved in the single market, but not in an FTA.”
Ms May has ruled out remaining in the single market and customs union and any arrangement which appeared to give the North a separate status would be resisted by the DUP, whose 10 MPs are effectively keeping Ms May in power after the Tories lost their majority in the June general election.
DUP leader Arlene Foster said: “We will not support any arrangements that create barriers to trade between Northern Ireland and the rest of the United Kingdom or any suggestion that Northern Ireland, unlike the rest of the UK, will have to mirror European regulations.”
Meanwhile, it emerged the UK could be required to follow new rules implemented by the EU during a Brexit transition period.
The position set out by Michel Barnier in leaked documents would make the application of new EU rules a condition of a transitional deal, meaning Britain could be subject to further Brussels’ regulations for two years after leaving the bloc.
Ms May hopes to secure an implementation period between the UK’s formal exit date and the commencement of any post-Brexit trade deal in order to give businesses time to adjust to the new arrangements, but accepting new rules could trigger a revolt by Eurosceptics.
It would also go against the approach to an implementation period set out by the prime minister in her Florence speech, where she said the “framework for this strictly time-limited period ... would be the existing structure of EU rules and regulations”.
British foreign secretary Boris Johnson has indicated that accepting further regulations from Brussels would cross a red line.