A BREXIT deal before October 31 looks “essentially impossible”, according to Number 10.

The downbeat assessment followed a phone call between Boris Johnson and the German Chancellor Angela Merkel this morning.

Less than a week after the Prime Minister sent Brussels his alternative to the Irish backstop, Mrs Merkel was reported to have said it was “overwhelmingly unlikely” to work.

The BBC reported a Number 10 source saying the call, which reflected EU reservations about the PM’s idea, had been a “clarifying moment”.

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Mr Johnson had proposed keeping Northern Ireland aligned with EU single market rules, but taking it out of the EU customs union, creating the need for controversial customs checks.

The plan also gave the pro-Brexit DUP an effective veto over the single market element.

Mrs Merkel was reported to have told the PM a deal depended on Northern Ireland staying in the customs union, creating an all-Ireland backstop.

This would harmonise EU rules and customs throughout Ireland, avoiding any internal checks, but would be seen by the DUP as splitting Northern Ireland from Great Britain.

According to the BBC, the Number 10 source said: "Talks in Brussels are close to breaking down, despite the fact that the UK has moved a long way."

Sky News also quoted a No 10 source as saying: "She [Mrs Merkel] has made clear a deal is overwhelmingly unlikely and she thinks the EU has a veto on us leaving the customs union."

Nicola Sturgeon tweeted: "The UK government's attempts to shift the blame for the Brexit fiasco to anyone but themselves - today it's Merkel - is pathetically transparent."

Shadow Brexit secretary Keir Starmer tweeted: "This is yet another cynical attempt by Number 10 to sabotage the negotiations.

HeraldScotland:

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"Boris Johnson will never take responsibility for his own failure to put forward a credible deal. His strategy from day one has been for a no deal Brexit.

"It is now more important than ever that Parliament unites to prevent this reckless Government crashing us out of the EU at the end of the month."

DUP leader Arlene Foster said: "The comments from the German Chancellor to the Prime Minister that Northern Ireland must remain in the EU Customs Union forever now reveal the real objective of Dublin and the European Union.

"For the United Kingdom to be asked to leave a part of its sovereign territory in a foreign organisation of which the UK would no longer be a part and over which we would have no say whatsoever is beyond crazy. No UK Government could ever concede such a surrender.

"The EU is not interested in a negotiated outcome at this time.

Their position is the UK can only leave with a deal if it agrees a binding piece of international law permanently tying either the whole country or a part of it to the EU's legal order over which it has no control.

"The true purpose of the 'backstop' is now in the open for an to see. Those who eagerly supported the backstop as the best of both worlds can now see the error of that assessment. It was neither temporary nor an insurance policy.

"The Prime Minister's proposals have flushed out Dublin's real intentions to trap Northern Ireland in the EU Customs Union forever, where Dublin rather than the United Kingdom's elected representatives would be in the driving seat.

"We will not accept any such ultimatum or outcome."

The briefings echo one given by a Number 10 source - suspected to be Mr Johnson’s chief adviser Dominic Cummings - to the Spectator magazine on Monday night.

This said that if Mr Johnson’s deal died within the next few days it would not be revived, and the Tories would fight a general election campaigning for a no-deal Brexit.

The source also reported the PM would try to scupper a Brexit extension, despite the law forcing him to seek one, by making it plain to EU leaders there was little point in granting it.

The person suggested there would be open hostility between the UK and any EU countries seen to be promoting a delay, despite any decision granting a delay having to be unanimous.

Former Home Secretary Amber Rudd told Radio 4 she suspected Mr Cummings was the author of the extensive text messages quoted by the Spectator, calling the language “angry and desperate”.

The Spectator's source suggested defence and security cooperation could be adversely affected if the UK fell out with other EU countries.

Labour MP Hilary Benn, chair of the Brexit Select Committee, tweeted: "I am afraid that this just demonstrates what a chaotic mess the Government has got itself into. Threats about security co-operation cannot be used as some kind of Brexit bargaining chip."