DUP leader threatens to withdraw support for Theresa May on Brexit customs plans

Arlene Foster has said ensuring Northern Ireland has the same arrangements as the rest of the UK is a ‘red line’

The leader of the DUP has warned that her party will withdraw its support for Theresa May’s government if it adopts a Brexit deal that sees Northern Ireland treated differently from the rest of the UK.

Arlene Foster said ensuring Northern Ireland maintains the same rules and regulations as Britain was a “red line” which if crossed would lose the Conservatives the critical backing of her 10 MPs.

It comes as cabinet ministers are still struggling to find a solution to fulfil two of Ms May’s key Brexit pledges – keeping the Irish border open and leaving the EU’s customs union.

Within weeks Ms May is expected at a European Council summit where her administration had once talked about reaching an agreement on customs with the EU.

Ms Foster told Sky News: “For us, our only red line is that we are not treated any different from the rest of the United Kingdom, that there are no trade barriers put up between Northern Ireland and our biggest market which, of course, is Great Britain.

“That’s what we will judge all of the propositions that are brought forward … against that red line and she’s very much aware of that.

“And I have confidence that she knows that she cannot bring forward anything that will breach that red line or we simply will not be able to support them.”

One idea reportedly proposed by Brexit secretary David Davis – and dismissed by Downing Street – would see Northern Ireland covered by a joint regime of UK and EU customs regulations, allowing it to trade freely with both, plus a 10-mile wide “special economic zone” on the border with Ireland.

Cabinet ministers were last month tasked with analysing the two main options so far put forward by civil servants for the Irish border, a “customs partnership” proposal that would see Britain continue to collect tariffs on behalf of the EU, and the technology-based “maximum facilitation”, or “max fac”, solution. Mr Davis’s idea was dubbed “max fac 2”.

But Brussels has already rejected both schemes, with chief Brexit negotiator Michel Barnier saying on Friday that neither was “operational or acceptable”.

EU leaders including Leo Varadkar, the Irish taoiseach, have called for progress by the time the European Council meets at the end of June, with Simon Coveney, Ireland’s deputy head of government, on Saturday also telling The Irish Times the UK must produce “written proposals” for the border within the next two weeks.

Sajid Javid, the home secretary, said on Sunday that the government was making progress with Brexit plans, saying: “I’m confident that as we get to the June council meeting, the prime minister will have a good set of proposals and our colleagues in Europe will respond positively.”

But shadow international trade secretary Barry Gardiner said the government’s refusal to remain in a customs union with the European Union would ensure the UK was a “minnow trying to compete against whales” on the global stage.

He told Sky News that Labour’s Brexit policy would ensure “trade in goods would continue uninterrupted”, adding: “The Tories’ red line is actually going to make it much, much more difficult.

“They’re the ones who will be isolated, they will be minnows trying to compete against whales.

“They will be a 70 million strong consumer market against America’s 500 million.”