PM insists he is ‘very confident’ his deal will be approved by parliament on Saturday

Boris Johnson has insisted he is “very confident” that his Brexit deal will be approved by the House of Commons in a historic knife-edge vote on Saturday, even without the backing of the DUP.

“I want to stress that this is a great deal for our country, for the UK; I also believe that it is a very good deal for our friends in the EU,” Johnson said at the European council in Brussels, where EU leaders signed off on the last-minute deal.

Johnson hopes to frame Saturday’s House of Commons clash as a dramatic “new deal or no deal” moment – but EU leaders declined to come to his aid in Brussels by ruling out any further delay to Brexit.

Boris Johnson gets his deal and a slap on the back in Brussels Read more

The arithmetic looks daunting for Johnson, after he opted to press ahead and sign up to a deal even after the DUP issued an early morning statement saying it could not support the government’s position.

Later, when the text of a reworked withdrawal agreement was published by the European commission, Arlene Foster’s party issued a more strident statement saying the agreement “drives a coach and horses through the professed sanctity of the Belfast agreement”.

Without the DUP’s 10 MPs, Johnson is likely to need the support of some Labour MPs and the 21 Conservatives he expelled from the parliamentary party for backing the Benn act last month.

Asked what he could offer to Labour MPs, he pointed to the “level playing field” assurances in the rewritten political declaration – the part of the deal relating to the UK’s future relationship with the EU.

But senior government officials had earlier made clear that the assurances were similar to those that would be included in any standard free trade agreement.

Meanwhile, the German chancellor, Angela Merkel, underlined the fact that the Johnson deal points the way to much looser economic ties than May’s agreement.

“At the time [under May], it wasn’t clear what the future relationship should look like, whether there would be a membership in the single market or not. Now it’s very clear that Britain’s going to be a third country and we will quickly begin negotiating a free trade agreement with that third country, Great Britain,” she said.

The shadow chancellor, John McDonnell, dubbed the deal a “sellout”, adding: “It’s not just the DUP – he’s sold out virtually every sector of our economy and all those who may have voted to leave believing a deal could be secured that protected their jobs.”

However, some of the so-called “Spartans” on the right wing of the Conservative party appeared ready to abandon the DUP and support Johnson’s deal.

Andrew Bridgen told Channel 4: “This is far more palatable to me. It looks like Brexit, it smells like Brexit, that’s Brexit for me, and I’m willing to suck up quite a lot in the withdrawal agreement that I don’t like in order to get to Brexit.”

Meanwhile, MPs backing a second referendum appeared to be backing away from tabling an amendment aimed at attaching a “people’s vote” to the deal, as Jeremy Corbyn declined to say whether Labour would back it. They are expected to decide on Friday how to proceed.

EU sources said Johnson had not directly asked leaders to rule out an extension during his address to them on Thursday afternoon, but that he had “made very clear his intention was to be out by 31 October”.

The prime minister had been helped in his attempts to create a cliff-edge by comments from Jean-Claude Juncker casting doubt on the possibility of a further Brexit delay, but the heads of state and government did not follow the European commission president’s lead.

Play Video 0:38 'It has to be now': Jean-Claude Juncker claims EU won't further delay Brexit - video

Juncker had told reporters earlier in the day that he was “ruling out” a “prolongation”, although the decision is outside his remit as commission president. “If we have a deal, we have a deal, and there is no need for prolongation,” he said. But one EU official conceded that the comments were “fake news” and that the view was not widely shared among the leaders.

A summit communique issued after two hours of discussion simply tasked the commission and European parliament with taking “the necessary steps to ensure that the agreement can enter into force on 1 November”.

Donald Tusk, the president of the European council, who will provide guidance on the options in the event of another rejection of a deal, said the issue of an extension was for a later date.

He said: “Our intention is to work towards ratification. We support a deal and this was a clear decision of the 27 member states. And we prepared for this ratification, politically, logistically, technically.

“Now the ball is in the court of the UK. I have no idea what will be the result of the debate in the House of Commons on Saturday. It isn’t for me to comment on political developments in the UK. But if there is a request for an extension, I will consult member states to see how they react.”

A senior EU official said that the leaders would follow events on Saturday, and reflect on the next steps if they were in a “different situation”.

A second diplomatic source said they had chosen not to interfere in a “sensitive domestic debate … but they leave the door open to the possibility of an extension, to be discussed at a later stage – if required”.

In a joint press conference, Tusk, Juncker, the Irish taoiseach, Leo Varadkar, and the EU’s chief negotiator, Michel Barnier, spoke of their “sadness” over Brexit.

“What I feel today is sadness,” Tusk said. “Because in my heart, I will always be a remainer. And I hope that if our British friends decide to return one day, our door will always be open.”

Play Video 0:29 Leo Varadkar says UK will always be welcome back in the EU - video

Varadkar said: “It’s a little bit like an old friend that’s going on a journey or an adventure without us, and we really hope it works out for them. But I think there will always be a place at the table for the United Kingdom if they ever chose to come back.”

Merkel said EU leaders had not focused on the question of extending Brexit talks, if the House of Commons voted down the deal on Saturday: “We have not taken any position … should A, B or C happen.” She added that it was “not a happy day for us”.

The PM is widely expected to make another bid to secure an early general election, whether or not his deal is endorsed on Saturday.

If MPs reject it, he is legally obliged under the Benn act to request a delay to Brexit – though senior government officials insisted again on Thursday that Johnson was determined to leave the EU on 31 October.

If he tries to frustrate the act – for example by sending a second, contradictory letter, that would set up a constitutional crisis that would have to be resolved in the courts.

But with an extension secured, he would then be likely to press for an election – and he devoted part of his short speech in Brussels to setting out manifesto-friendly pledges.