The UK has set the EU a deadline of just two days to begin intensive talks on Boris Johnson’s new Brexit proposals, risking a new rupture in relations with Brussels.

Stephen Barclay, the Brexit secretary, said negotiations had to “move forward at pace”, with the crucial summit at which an agreement must be reached just two weeks away.

He ducked a question about whether an EU refusal to begin talks so quickly – after its overnight criticisms of the prime minister’s blueprint – would mean the plan “is not going to fly”.

No 10 has already hinted that the prime minister may boycott the Brussels summit on 17 October unless intensive talks begin straight away – which would bring any hope of a deal crashing down.

The EU is determined not to be blamed for such a failure, prompting Jean-Claude Juncker, the EU Commission president, to point to “positive advances” in the UK’s new plan.

However, behind the scenes, his negotiator Michel Barnier, is believed to have warned that handing Stormont a veto on whether to align with EU or UK regulations would leave the EU “trapped” and imperil the single market.

Supreme Court protests: Boris Johnson's prorogation legal or not? Show all 15 1 /15 Supreme Court protests: Boris Johnson's prorogation legal or not? Supreme Court protests: Boris Johnson's prorogation legal or not? Protesters gather outside The Supreme Court ahead of a hearing on the legality of Boris Johnson's proroguing of Parliament Getty Supreme Court protests: Boris Johnson's prorogation legal or not? The supreme court justices will sit as a panel of 11 judges to hear the challenge, brought by campaigner Gina Miller, that the Prime Minister acted unlawfully when he advised the Queen to suspend parliament AP Supreme Court protests: Boris Johnson's prorogation legal or not? A woman protests outside the Supreme Court Reuters Supreme Court protests: Boris Johnson's prorogation legal or not? The PM sent lawmakers home on 9 September until 14 October, just over two weeks before the UK is due to leave the European Union AP Supreme Court protests: Boris Johnson's prorogation legal or not? Gina Miller arriving AP Supreme Court protests: Boris Johnson's prorogation legal or not? People protest outside the Supreme Court Reuters Supreme Court protests: Boris Johnson's prorogation legal or not? Boris Johnson likened himself to the Incredible Hulk days previous as he promised to ignore the Commons legislation ordering him to delay Brexit if negotiations break down PA Supreme Court protests: Boris Johnson's prorogation legal or not? Officials bring in documents Reuters Supreme Court protests: Boris Johnson's prorogation legal or not? Protesters hold banners outside the Supreme Court in London, Tuesday Sept. 17, 2019. The Supreme Court is set to decide whether Prime Minister Boris Johnson broke the law when he suspended Parliament on Sept. 9, sending lawmakers home until Oct. 14 â€” just over two weeks before the U.K. is due to leave the European Union. (AP Photo/Matt Dunham) Matt Dunham AP Supreme Court protests: Boris Johnson's prorogation legal or not? Protesters hold banners outside the Supreme Court in London, Tuesday Sept. 17, 2019. The Supreme Court is set to decide whether Prime Minister Boris Johnson broke the law when he suspended Parliament on Sept. 9, sending lawmakers home until Oct. 14 â€” just over two weeks before the U.K. is due to leave the European Union. (AP Photo/Matt Dunham) Matt Dunham AP Supreme Court protests: Boris Johnson's prorogation legal or not? Protesters hold banners outside the Supreme Court in London, Tuesday Sept. 17, 2019. The Supreme Court is set to decide whether Prime Minister Boris Johnson broke the law when he suspended Parliament on Sept. 9, sending lawmakers home until Oct. 14 â€” just over two weeks before the U.K. is due to leave the European Union. (AP Photo/Matt Dunham) Matt Dunham AP Supreme Court protests: Boris Johnson's prorogation legal or not? People protest outside the Supreme Court of the United Kingdom during a hearing on Prime Minister Boris Johnson's decision to prorogue parliament, in London, Britain September 17, 2019. REUTERS/Phil Noble PHIL NOBLE Reuters Supreme Court protests: Boris Johnson's prorogation legal or not? Protesters hold banners outside the Supreme Court in London, Tuesday Sept. 17, 2019. The Supreme Court is set to decide whether Prime Minister Boris Johnson broke the law when he suspended Parliament on Sept. 9, sending lawmakers home until Oct. 14 â€” just over two weeks before the U.K. is due to leave the European Union. (AP Photo/Matt Dunham) Matt Dunham AP Supreme Court protests: Boris Johnson's prorogation legal or not? Joanna Cherry of the Scottish National Party leaves the Supreme Court Reuters Supreme Court protests: Boris Johnson's prorogation legal or not? Demonstrators protest outside the Supreme court in central London on the first day of the hearing into the decision by the government to prorogue parliament on September 17, 2019. (Photo by Tolga Akmen / AFP)TOLGA AKMEN/AFP/Getty Images TOLGA AKMEN AFP/Getty

Meanwhile, MEPs are expected to announce that they will reject the plan in its current form as early as today.

Asked when formal negotiations would begin, Mr Barclay said: “We need to move forward at pace intensively.”

Asked if that mean Brussels must agree to start work on the blueprint by the weekend, he told BBC Radio 4’s Today programme: “Yes.”

The “two borders” plan – a customs barrier in Ireland, with inevitable checks, and oversight of the regulatory border between Northern Ireland and Great Britain – crosses EU red lines in several ways.

Tony Lloyd, Labour’s shadow secretary of state for Northern Ireland, said he was certain neither Brussels nor Dublin would compromise on something “so fundamental”.

“This is simply not Good Friday Agreement compatible. It simply doesn't do that,” Mr Lloyd said.

And Trevor Lockhart, group chief executive at Fane Valley Co-op, an agri-food business in Northern Ireland, said its interests “have now been sacrificed”.

“As they currently stand, the government proposals don't represent a final destination for Northern Ireland business,” he warned.

But Mr Barclay insisted the UK commitment of no customs-checking infrastructure at the border meant it stood by “our commitment to the Belfast Good Friday Agreement”.

And he dismissed fears about smuggling, saying: “It's about what is proportionate. Most smuggling operations aren't actually addressed at a border.

"Most smuggling is actually addressed in terms of intelligence, in terms of information-sharing, in terms of close partnership between the various agencies.”