MICHEL Barnier has issued a stark warning that there is currently no basis for a Brexit deal as the UK prepares to leave the EU in just 21 days.

Ahead of next week’s crucial EU summit, the European Commission’s chief negotiator said he and his team had yet to see any “operational, legally binding solution” to the issue of the Northern Ireland backstop aimed at preventing a return to a hard border.

Addressing MEPs, he said Boris Johnson’s proposals – under which Northern Ireland would align itself with the EU’s single-market rules but not remain inside the customs union – were based on a system “that hasn’t been properly developed, that hasn’t been tested”.

Johnson’s hopes of securing a deal in time for the summit on October 17 and 18 could now rest on a meeting with Irish Taoiseach Leo Varadkar which could take place today.

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In his address to the European Parliament, Barnier said the EU would continue to work in a “calm” and “constructive” manner to try to find an agreement.

But he made clear Johnson’s blueprint – which would require the return of customs checks on the island of Ireland – was not the basis for a solution.

“To put things very frankly, though, and to try and be objective, [at] this particular point, we are not really in a position where we are able to find an agreement,” he said.

“The proposal of the British Government as things stand is not something we can accept. It replaces an operational, practical, legal solution with one that is simply a temporary solution.”

Following a series of acrimonious exchanges between London and Brussels on Tuesday, European Commission president Jean-Claude Juncker told the parliament they would not get drawn into a “blame game”.

“Personally I don’t exclude a deal. We are, Michel and myself, working on a deal. And we are not accepting this blame game which started in London,” he said.

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As Juncker and Barnier spoke it emerged the DUP and senior Tory Eurosceptics rejected a new concession from the EU which provides a mechanism for the Northern Ireland assembly to leave the backstop.

Diplomatic sources said European governments are prepared to concede a unilateral revocation of the withdrawal treaty by Stormont after a period of time. The date of 2025 has been mooted, as long as both communities agree to it. Under the new proposals Northern Ireland would stay in the customs union and single market until a “double majority” at Stormont — of unionists and nationalists — votes to leave.

However Sammy Wilson, the DUP’s Brexit spokesman, said: “It will go nowhere.”

Iain Duncan Smith, the ex-Tory leader, said: “This is about shifting the blame to Boris Johnson.”

Attention is turning in some European capitals to the length of a Brexit delay the PM will be compelled to seek under the Benn Act. While some MPs are hoping for a long delay at least one EU government backs a shorter one. Earlier this week a poll of six European countries found voters were opposed to offering any extension beyond October 31. In France, 57% rejected any extension, rising to 66% in Germany.