Ireland has told Boris Johnson that it needs to see his proposals to solve the Irish border problem by next week, ramping up the pressure on the embattled prime minister as the clock ticks down to the 31 October exit date.

Leo Varadkar threw his weight behind an unofficial deadline set by Emmanuel Macron and the EU presidency, who had said proposals need to be in by the end of the month or “it’s over”.

The demand puts the UK and the EU on a collision course ahead of a make-or-break summit later in October, where Mr Johnson will meet EU27 leaders as a group for the first time.

Though technical talks continued in Brussels on Wednesday, Downing Street has said it will not be bound by “artificial deadlines”, while the Brexit secretary Stephen Barclay has even suggested that plans for the border can wait until the end of next year.

“We have working methods and I know that President Tusk and other EU heads of government would like to see British proposals in writing really in the first week of October, otherwise it is very hard to see how we could agree something at the summit in the middle of October,” the taoiseach told reporters at the UN general assembly in New York.

“The withdrawal agreement is actually an international treaty. It’s not the kind of thing that can be amended or cobbled together late at night at the European Council meeting on 17th of October.

“So if the UK does have meaningful proposals, changes that they would like to suggest to the withdrawal agreement or to the joint political declaration more particularly, we really need to see them in advance so that they can be worked through and worked up in advance of the EU summit.”

Brussels officials and diplomats have warned that “concepts” put forward by the UK so far in a series of confidential off the record “non-papers” fall far short of anything close to replacing the Irish backstop, which Mr Johnson has said he cannot accept.

Guy Verhofstadt, the European parliament’s Brexit chief, again on Wednesday said the two sides were “still far from a deal”.

Supreme Court verdict: Boris Johnson prorogation unlawful Show all 16 1 /16 Supreme Court verdict: Boris Johnson prorogation unlawful Supreme Court verdict: Boris Johnson prorogation unlawful The Supreme Court has ruled against Boris Johnson by declaring his government unlawfully shut down parliament for five weeks EPA Supreme Court verdict: Boris Johnson prorogation unlawful Lady Hale handed down the historic verdict, hailed by opposition MPs and anti-Brexit campaigners. She said all 11 judges were unanimous in deciding that the case is “justiciable”, so the government loses that part of the argument. “The court is bound to conclude therefore that the decision to advise Her Majesty to prorogue was unlawful because it had the effect of frustrating or preventing the ability of Parliament to carry out its constitutional functions.” EPA/Supreme Court Supreme Court verdict: Boris Johnson prorogation unlawful Gina Miller and her team react outside the Supreme Court are the verdict. She said: “Today is not a win for any individual or cause. It is a win for Parliamentary sovereignty, the separation of powers and independence of our British courts. Crucially, today’s ruling confirms that we are a nation governed by the rule of law, laws that everyone, even the Prime Minister, are subject to." PA Supreme Court verdict: Boris Johnson prorogation unlawful A person dressed as a caricature of British Prime Minister Boris Johnson in a prison uniform stands outside the Supreme Court AP Supreme Court verdict: Boris Johnson prorogation unlawful Labour leader Jeremy Corbyn called for Mr Johnson to “consider his position” following the landmark decision, while Lib Dem leader Jo Swinson said he was “not fit to be prime minister” Getty Supreme Court verdict: Boris Johnson prorogation unlawful Scottish National Party (SNP) Westminster leader Ian Blackford raises his arms as he comes outside. He said: "This is an absolutely stunning judgement by the Supreme Court today." He went on to say, "we all want to get back to work, and quite frankly, on the back of this, Boris Johnson must resign immediately." AFP/Getty Supreme Court verdict: Boris Johnson prorogation unlawful Crowds outside celebrated the verdict AP Supreme Court verdict: Boris Johnson prorogation unlawful Delegates at the Labour party conference applaud after hearing the news AFP/Getty Supreme Court verdict: Boris Johnson prorogation unlawful Speaker John Bercow said MPs must now “convene without delay” and confirmed the Commons would return at 11.30am on Wednesday AFP/Getty Supreme Court verdict: Boris Johnson prorogation unlawful Gina Miller said: "“As a result of this judgment, Parliament is open, it was never prorogued. I urge MPs to get back to work immediately.” AP Supreme Court verdict: Boris Johnson prorogation unlawful MPs Anna Soubry, Liz Saville Roberts and Caroline Lucas, together with SNP leader Ian Blackford, react. Green MP Caroline Lucas has said the Supreme Court’s decision is “just the start” Reuters Supreme Court verdict: Boris Johnson prorogation unlawful “The UK deserves a Prime Minister and a Government who act with honesty, integrity and in a manner consistent with our constitution, at all times." AFP/Getty Supreme Court verdict: Boris Johnson prorogation unlawful Anti-Brexit supporters react as they gather outside the Supreme Court in London, Tuesday, Sept. 24, 2019 as it makes it's decision on the legality of Prime Minister Boris Johnson's five-week suspension of Parliament. (AP Photo/Frank Augstein) Frank Augstein AP Supreme Court verdict: Boris Johnson prorogation unlawful The SNP’s Joanna Cherry QC says: “Boris Johnson’s position is untenable and he should have the guts to resign.” PA Supreme Court verdict: Boris Johnson prorogation unlawful epa07865617 Protesters react outside the Supreme Court after the result of a hearing on the prorogation of parliament, in London, Britain, 19 September 2019. The Supreme Court ruled that the suspension of parliament by British Prime Minister Boris Johnson was not lawful. EPA/NEIL HALL NEIL HALL EPA Supreme Court verdict: Boris Johnson prorogation unlawful Tom Tugendhat MP returned to the chamber in the House of Commons within minutes of the Supreme Court ruling PA

“They are not meeting the three conditions,” he said. “This point is not solved and this backstop needs to be in place as it is for them. We have already said from day one that if they want to change the backstop, they can go to the one they first proposed because the backstop as it is now was at the request of the UK government.

“It was not the initial proposal of the EU side or whatever European negotiator. We wanted a Northern Ireland backstop only and also for the good reason that the majority of Northern Ireland voted against Brexit, so let’s not forget that.”

Boris Johnson returned from New York on Wednesday (Reuters) (REUTERS)

EU chief negotiator Michel Barnier told reporters earlier this week that “the current state” of UK thinking on the issue meant that a replacement for the backstop looks improbable, and that it was “difficult to see” a deal being reached.

Boris Johnson has said the UK will be leaving the EU at the end of October “do or die”, raising the prospect of a no deal – though parliament has legislated to instruct him to demand an extension to avoid Britain crashing out. Any extension would be subject to unanimous approval by EU member states, with some more positive about the idea of prolonging the crisis than others.

The UK’s outlines of its plans presented in talks so far, which have not yet been fleshed out beyond “concepts”, involve Northern Ireland being aligned with the EU on some rules such as agriculture, known as SPS – but only with the say-so of the Stormont assembly. Northern Ireland would also remain part of a single Ireland electricity market.

But in other areas, such as manufactured goods and industrial goods, various “facilitations” would be employed so that there were checks and controls for products moving between Ireland and Northern Ireland, but they were carried out away from the border.