Boris Johnson's humiliation at the hands of Luxembourg will make a Brexit deal harder to reach and could make a no-deal more likely, some on the EU side believe.

Norbert Röttgen, chair of the German parliament's foreign affairs committee and a senior MP from Angela Merkel's party, was among those to publicly criticise the Luxembourg prime minister Xavier Bettel on Tuesday.

Mr Bettel had strongly criticised Mr Johnson and the UK government and empty-chaired the British prime minister after he refused to take part in a planned press conference in Luxembourg on Monday.

"Xavier Bettel’s speech yesterday did not serve the European cause," Mr Röttgen, a former minister in Ms Merkel's government warned.

"His public venting ignored that a deal is still in everyone’s interest. Even without a deal there will be a post-Brexit life, which means that right now everyone needs to behave in a way that avoids animosity."

One EU diplomat in Brussels suggested that Mr Bettel had gone too far and "reinforced the us versus them narrative" in the UK.

Another accused Luxembourg's leader of playing into the hands of hard Brexiteers back in the UK who wanted a no-deal.

Mr Johnson's reception in Luxembourg was at odds with the diplomatic approach taken by Angela Merkel and Emmanuel Macron to the new prime minister in recent visit to Berlin and Paris.

Then, rhetoric was kept on a leash and both leaders had stressed that they were open to looking at any concrete solution that the UK could produce to replace the backstop.

However, with no proposals from the UK forthcoming after nearly a month since Boris Johnson set himself a 30-day deadline, patiences are fraying across the continent.

During Monday's visit Mr Bettel warned an absent Mr Johnson that that the “clock is ticking”, adding on Monday: “Stop speaking and act.”

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

But the comments enraged Conservatives back in Westminster. Even pro-EU figures such as Sir Nicholas Somes, who has lost the Tory whip, criticised what he called the "very poor behaviour" of the Luxembourg government.

Former Conservative leader Iain Duncan Smith dredged up memories of the Second World War, saying: “The irony is that Luxembourg was saved by Britain. National leaders should always treat one another with courtesy and civility. Good ones do.”