Brexit: Remain in customs union and single market to solve border issue, Ireland's European commissioner tells May

'The best possible 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,' says Phil Hogan

Theresa May faces fresh pressure over the Irish border issue (EPA)

Theresa May is facing fresh pressure to change course over plans for the Northern Irish border after Brexit as Ireland’s EU commissioner stepped up threats to veto trade talks.

Rows over the prospect of a hard border on the island of Ireland are threatening to derail negotiations as the EU has said “sufficient progress” must be made before talks can begin on a UK-EU trade deal after Britain leaves the bloc.

Commissioner Phil Hogan called for the UK to remain in the customs union and single market – or allow Northern Ireland to do so – but the Prime Minister’s DUP allies have vowed they will not tolerate any attempts to keep Northern Ireland within the trade agreements.

It comes as leaked papers seen by The Independent revealed fresh challenges for Ms May as EU negotiators are already laying the groundwork to hit the UK with demands that will be unacceptable to members of her Cabinet.

The Prime Minister has been given until 4 December 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 Ireland would "play tough to the end" over the border issue, and 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 Government’s approach to Brexit he told the 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 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.”

My May has ruled out remaining in the single market and customs union and any arrangement which appeared to give Northern Ireland a separate status would be strongly resisted by the DUP, whose 10 MPs are effectively keeping Mrs May in Downing Street after she lost her majority in the general election.

DUP leader Arlene Foster told her party conference on Saturday: “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 about 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 the imposition of 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”.

Foreign Secretary Boris Johnson has already indicated that accepting further regulations from Brussels would cross a red line.

The Prime Minister was also under pressure not to water down a red line on the European Court of Justice’s jurisdiction ending when the UK leaves the EU, with lobbying from senior Tories over plans to push a "voluntary referral" of cases to the ECJ.