Arlene Foster says she is ready to fly to London to examine finer points of Brexit agreement on Irish border

Arlene Foster, the DUP leader, has said there is “still work to be done in London” after her short telephone call to the prime minister on Wednesday morning over the Irish border issue in the Brexit talks.

Following her conversation with Theresa May, the DUP said Foster was ready to fly to London to examine the finer points of any agreement.

The pair spoke on the phone on Wednesday morning, after Foster declined to take the prime minister’s calls for 24 hours while their officials were thrashing out their differences over No 10’s proposed deal with the EU.

May and Foster agreed that staff from both sides would continue to work on the issue of the Irish border – with the DUP concerned about the scope of a promise of continued regulatory “alignment” in the event of no deal.

Earlier, Foster said the latest furore could have been avoided if her party had had a seat at the table in the Brexit talks. “There is a need for us to be directly involved,” she said.

Referring to the debacle earlier this week over the leaked document, which suggested a post-Brexit deal for the Irish border based on a “regulatory alignment” in terms of trade on the island, Foster said: “If we had been involved directly in the process, in the room, I don’t think we would have arrived at such a stark situation.”

The DUP expressed its shock at May’s handling of the talks on Tuesday and appeared to be in little hurry to reach a deal, despite the UK and the EU hoping to sign off an agreement this week.

A government source said the prime minister stood ready to travel to Brussels when Britain believes it is in a position to clinch a deal – but that is not expected to be on Wednesday.

A spokesman said: “The prime minister said earlier this week we’re making good progress and there’s more work to do. We remain focused on making more progress at the December European council.”

May had hoped to settle the issue of the Irish border with the EU on Monday but did not appear to have sufficiently consulted her political partners in the DUP, whose 10 MPs prop up her minority government.

The UK was prepared to sign up to the idea of “regulatory alignment” between Northern Ireland and the Republic of Ireland, in specific areas such as agriculture and energy, potentially applying across the whole of the UK.

However, hopes of a deal fell apart after the DUP said it did not have assurances that No 10 was doing enough to make sure Northern Ireland got exactly the same Brexit deal as the rest of the UK.

In a further headache for May, senior leave-supporting Tories, including the foreign secretary, Boris Johnson, are unhappy about the idea of the whole of the UK signing up to any “regulatory alignment” with the rest of the EU, as they believe it would defeat the point of Brexit.

One senior government source said the Brexiters were keen to “bottom out” the implications of the wording in the proposed agreement.

Separately, Sinn Féin warned on Wednesday that Ireland must not be “collateral damage” in any attempt to keep the Tory/DUP pact at Westminster alive. The Sinn Féin MP for Foyle, Elisha McCallion, said: “The solution to Britain’s Brexit crisis in Ireland is clear. The north of Ireland should have designated special status within the EU ensuring that we remain within the customs union and the single market.

“That is the only guarantee of stability and certainty and delivers the full protection of the Good Friday agreement in all its parts, including Irish citizenship and the benefits of EU citizenship.

“This is a commonsense, practical, and achievable proposal and does not change the constitutional position of the north.”

The DUP leader also sought to repair some of the damaged relations with the Irish government on Wednesday. She described the taoiseach, Leo Varadkar, as a friend but accused him of taking the “Sinn Féin line” on Brexit talks.

Only last month Foster stood side by side with Varadkar at the war memorial in Enniskillen on Remembrance Sunday – the spot where an IRA bomb had killed 11 Protestant civilians on Poppy Day in 1987.