Nigel Dodds, the DUP's Westminster leader, urged the Prime Minister to reconsider his Brexit offer and ensure the United Kingdom leaves the EU as one.

He voiced concerns over the impact of the proposed agreement on Northern Ireland and reminded Mr Johnson about previous commitments he had given.

Speaking in the Commons, Mr Dodds told the PM: "Weariness in this House over Brexit should not be an excuse for weakness on Brexit or weakness on the union."

Nigel Dodds, the DUP's Westminster leader, urged the Prime Minister to reconsider his Brexit offer. Picture: Getty Images

Mr Dodds said there must be "Brexit for the whole of the United Kingdom", leaving the single market and customs union as one.

He said: "This deal puts Northern Ireland, yes, in the UK customs union but applies de facto all the European customs union code, yes it does, read the detail."

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Mr Dodds raised concerns over Northern Ireland's involvement in the VAT regime and the single market "without any consent up front" before claiming: "It drives a coach and horses through the Belfast Agreement by altering the cross-community consent mechanism."

Mr Dodds then alluded to previous warnings from Mr Johnson about how no British PM could agree to such terms, adding: "Will he now abide by that and please reconsider the fact that we must leave as one nation together?"

Mr Johnson, replying to Mr Dodds, said together he and the DUP secured changes on the customs union before defending the measures in the deal for Northern Ireland.

He said: "In all frankness I do think it a pity that it is thought necessary for one side or the other in the debate in Northern Ireland to have a veto on those arrangements.

"Because after all, I must be very frank about this, the people of this country have taken a great decision embracing the entire four nations of this country by a simple majority vote that went 52-48, which we're honouring now.

"I think that principle should be applied elsewhere and I see no reason why it should not be applied in Northern Ireland, and it is in full compatibility with the Good Friday Agreement."

"Considerable anxiety and anger"

Independent MP Lady Hermon (North Down) said: "The Prime Minister will be well aware of the considerable anxiety and indeed anger caused to the unionist community in Northern Ireland since the publication of his Brexit deal.

"I would like the Prime Minister to take this opportunity, since he has not bothered until now, to reach out and reassure the unionist community, I would like him to take this opportunity, publicly, to reassure the people in Northern Ireland that there is nothing in his deal which undermines the constitutional status of Northern Ireland as guaranteed by the Belfast/Good Friday Agreement and the consent principle.

"I pay tribute to the Taoiseach Leo Varadkar who has made a very, very solemn explanation and commitment about his commitment to the constitutional status of Northern Ireland, but as a unionist, I need to hear a British prime minister making that commitment to the unionist community."

Mr Johnson replied: "I am grateful to the right honourable lady and I wish to reassure her that I make an absolute commitment to the constitutional status of Northern Ireland which is inviolable and in tact.

"And it may be that she hasn't seen the statement from Lord Trimble who said of the change in the agreement that we have secured: 'Whilst previously the people in Northern Ireland were to have an agreement imposed on them, now we have a mechanism for the consent of the people of Northern Ireland and that is fully in accordance with the Good Friday Agreement'."

DUP Sammy Wilson (East Antrim) warned: "Rather than a great deal, this will do a great deal of damage to the Union."

Mr Johnson replied: "It is being done by consent, it is a very, very ingenious scheme that gets Northern Ireland out of the customs union and allows the whole of the UK to do free trade together with minimum, minimum bureaucracy."

Brexit deal vote: Brexit weariness is no excuse for weakness, DUP tells Boris Johnson