THERE will be “no more pointless delay” to Brexit, James Cleverly, the Conservative Chairman, has insisted as Boris Johnson prepares to make his “take it or leave it” offer to the EU, the details of which are due to be set out in his keynote speech to the Tory conference in Manchester today.

As the first details seeped out about the Prime Minister’s first and final offer to Brussels, the so-called “two borders for four years” proposal, the initial response from across the continent ranged from quizzical to downright hostile. One diplomatic source suggested it would go down “like a bucket of sick” with some in the EU27.

But, crucially, it seems that Mr Johnson, who received a hero’s welcome at a Democratic Unionist fringe event at the Tory conference last night, has got the backing of the DUP, who are said to be “content” with the PM’s blueprint to ditch the backstop.

The plan, dubbed “two borders for four years,” would involve Northern Ireland, from the end of the transition period in December 2020 until the start of 2025, staying in the regulatory aspects of the single market for agri-food and manufactured goods – meaning there would be a regulatory border down the Irish Sea between Northern Ireland and Great Britain – but joining the rest of the UK outside the customs union, meaning there would have to be customs checks between Northern Ireland and the Irish Republic.

Crucial to the plan – and the DUP’s support for it - would be a so-called “Stormont lock,” by which after four years, the Northern Ireland Assembly – which it is hoped will be resumed during the transition period - would decide whether or not to remain aligned with EU regulations or return to those across the rest of the UK.

The British-Irish ministerial council, which was set up under the Good Friday Agreement but has not sat for three years, would be restored. Representatives from the Northern Ireland Assembly and the Irish Dail would have oversight on the future regulatory regime on the island of Ireland.

This afternoon, Mr Johnson will set out to the party faithful details of a “fair and reasonable compromise” that he believes both sides can agree and build upon.

After 70 days of negotiations the fresh legal texts for the new proposed deal will be presented to Brussels later today. But No 10 made clear that this would be the final offer.

Dominic Cummings, Mr Johnson's de facto chief of staff, is said to have told senior officials that if Brussels declined to engage, then Britain would walk away from the negotiating table. "To be clear, we won't be hanging around waiting for them to negotiate with us. If they reject our offer, that's it," he reportedly said.

On ITV’s Good Morning Britain, Mr Cleverly declared: "No more pointless delay. This is the time for the EU negotiators to recognise that a deal can be done. It will require some flexibility but a deal can be done."

But across the Irish Sea, Mr Johnson’s “take it or leave it” plan is expected to be met with strong opposition from the Government in Dublin for jeopardising the Good Friday Agreement as well as the integrity of the single market.

One insider with knowledge of the Johnson Plan said it would leave Northern Ireland “marooned with frictionless trade with no one”.

At the DUP fringe, met under the slogan of “Together for the Union,” Mr Johnson admitted the UK-EU talks were “not a walk in the park,” progress had been made but there was a “long way to go”.

He told the BBC: “We’re going to work very hard. It’s a question of trying to get some progress…There is a landing zone, there is a great opportunity to get this done. But we will have to see how we get on.”

Asked if the DUP was backing the Johnson Plan, Arlene Foster, its leader, said her party continued to work very closely with the PM.

She told Radio Four’s Today programme: “I hope we do get a deal that is acceptable to the EU and one that is good for the whole of the UK. What people need to remember after the Withdrawal Agreement and the backstop came out, what was happening was that Northern Ireland was going to be in a different customs union, we were going to be in separate regulations without any democratic say and it is important we now try to get a deal that is good for Northern Ireland as well as the rest of the UK.”

At a reception thrown by the Irish Embassy, John McGrane, Director-General of the British-Irish Chamber of Commerce, said the organisation was “beyond nervous”. He added there was a frustration on all sides that progress had not been made during three years of talks.

Julian Smith, the Northern Ireland Secretary, noted: “We’re talking about the first stage of Brexit. It’s all to play for for the second stage. Let’s get this first stage done, get behind the Prime Minister and make sure we deliver in the best interests of the whole of the UK.”