British prime minister Boris Johnson: ‘I am very confident that when my colleagues in Parliament study this agreement that they will want to vote for it on Saturday and in succeeding days.’ Photograph: Stephanie Lecocq/EPA

The European Union's Brexit negotiator Michel Barnier outlines the main elements around the Brexit deal agreed between the EU and the UK. Video: EU Commission

Boris Johnson has said he is “very confident” MPs will back his last-minute Brexit deal despite the Democratic Unionist Party (DUP) ruling out its support.

The prime minister urged parliamentarians to “come together and get this thing done” after EU leaders approved the departure agreement hammered out shortly before the key summit began on Thursday.

Mr Johnson faces an uphill battle to get the deal backed during an extraordinary sitting of Parliament on Saturday, after his key and influential allies in the DUP rejected it.

Speaking at a press conference in Brussels, Mr Johnson appealed to those in Northern Ireland as well as across party lines in order to encourage support for the deal.

“I am very confident that when my colleagues in Parliament study this agreement that they will want to vote for it on Saturday and in succeeding days,” he said.

No extension European Commission president Jean-Claude Juncker appeared to rule out an extension to Brexit this afternoon following a deal reached with the UK over the terms of its departure from the European Union.

Speaking to reporters , Mr Juncker was asked whether he would rule out an extension to the Brexit deadline.

He responded that half an hour ago “I gave a brief doorstep . . . I was ruling out that there will be any kind of prolongation. If we have a deal we have a deal and there is no need for prolongation. That’s not only the British view that’s my view too.”

Any decision on an extension is the prerogative of EU heads of government. Earlier on Thursday, Mr Johnson said the “great new” Brexit deal had been agreed “that takes back control”.

Mr Juncker said on Twitter: “Where there is a will, there is a #deal - we have one! It’s a fair and balanced agreement for the EU and the UK and it is testament to our commitment to find solutions. I recommend that #EUCO endorses this deal. (Read the full text of the agreement here).

In a letter to European Council president Donald Tusk ahead of Thursday’s European Council summit, Mr Juncker gave the agreement his backing.

“While I deeply regret the outcome of the referendum of 23 June 2016, I continue to believe that the European Union is best served by an orderly and amicable withdrawal of the United Kingdom from our Union,” he wrote.

“Our hand should always remain outstretched as the United Kingdom will remain a key partner of the European Union in the future.

“The negotiators reached an agreement on a revised Protocol on Ireland/Northern Ireland and on a revised Political Declaration on 17 October 2019. Both were endorsed by the European Commission. The Prime Minister of the United Kingdom also signalled his approval of these documents to me today . . .

“As I have indicated to you in the past, I believe it is high time to complete the withdrawal process and move on, as swiftly as possible, to the negotiation on the European Union’s future partnership with the United Kingdom.”

Four main aspects The European Commission’s chief negotiator, Michael Barnier, held a press conference to announce the deal. He outlined four main aspects of it:

(1) Northern Ireland to remain aligned to “a limited range” of single market regulations on goods. That will require checks of goods in the Irish Sea. The North will remain in the UK customs area, but the UK will apply the EU’s customs code in the North. That will require customs checks in the Irish sea on goods except those not at risk of entering the EU. However, it will also mean that the North benefits from future UK trade deals.

(2) On Vat, arrangements have been made to maintain the integrity of the single market Vat rules, but they will satisfy the “legitimate wishes” of the UK.

(3) There will be provision to ensure “long term democratic support” for these arrangements in the North. Four years after their entry into force, the elected representatives of Northern Ireland will decide by simple majority to continue them or not, Mr Barnier said.

(4) This replaces the original backstop, and is not a transitional arrangement. This is the end state agreement on the North. “What really matters is the people,” Mr Barnier said. “What really matters is peace.”

On the future EU-UK relations, “level playing field” provisions have been agreed which will enable a future zero tariff-no quota free trade agreement. This means that the UK will not undercut the EU on standards, environmental regulations, labour laws, etc.

“The text of the agreement is now available,” he said. “I hope you enjoy reading it.”

DUP leader Arlene Foster. File photograph: Niall Carson/PA No DUP support Focus will now switch to Westminster as the DUP said they would not be supporting the deal.

In a statement released at lunchtime, the party reiterated its earlier statement opposing the deal, setting up a crucial sitting of the House of Commons on Saturday where the deal must be endorsed. It makes it more difficult for Mr Johnson to get the deal passed in parliament where the Tory government has a minority government that has relied on DUP support.

“Following confirmation from the Prime Minister that he believes he has secured a ‘great new deal’ with the European Union the Democratic Unionist Party will be unable to support these proposals in Parliament,” the party said in a statement on Thursday at lunchtime.

The stance of the DUP is important because the party wields influence over some Tory Brexiteers, including the ERG group within that party. However, there are some indications members of the ERG may back the deal even if the DUP remains opposed.

Britain’s Labour leader Jeremy Corbyn said his party cannot support the Brexit deal. “As it stands we cannot support this deal . . . also it is unclear whether it has the support of his allies in the DUP, or indeed, many allies on his own backbenches,” he said.

Earlier on Thursday Mr Johnson’s last-ditch attempt to clinch a Brexit deal was thrown into disarray just hours before the European Union summit when the DUP said it could not support the agreement.

In an early morning statement, DUP leader Arlene Foster and deputy leader Nigel Dodd said they “could not support what is being suggested on customs and consent issues” and that there is a “lack of clarity on VAT”.

Mr Johnson had promised to take Britain out of the EU on October 31st come what may, despite a law that requires him to request an extension if no deal is done and approved by parliament by Saturday. – Additional reporting Reuters/PA