OCTOBER will be the “moment of truth,” Michel Barnier has insisted.

The EU’s chief negotiator, speaking to reporters in Brussels, explained that at the European Council on October 18/19 both the EU and the UK will know if it is deal or no deal.

"October is the key point in time; it is the moment of truth,” declared Mr Barnier. “We will see whether an agreement is in reach at that moment based on a subjective evaluation which I will be submitting in reporting to the European leaders on the state of negotiations."

But there was more. The EU negotiator confirmed, as had been suggested earlier this week, that Brussels was working on a new plan to solve the conundrum of the Irish border. Having earlier rejected Theresa May’s plan for a facilitated customs arrangement based on technology, it seems Mr Barnier’s team has been working on a variation.

The Prime Minister’s objection to Brussels’ earlier plan, to effectively keep Northern Ireland in the customs union and which would have placed the border with the Republic down the Irish Sea, was anathema to the UK Government, not to mention the Democratic Unionists, who prop it up at Westminster.

But now, Mr Barnier, revealed, there was a Plan B; an "improved" proposal.

He explained: “What we are talking about here is not a border - not a land border, not a sea border; it is a set of technical checks and controls."

Stressing he wanted to maintain the integrity of the UK, the EU negotiator went on: “I hope on the basis of simple, practical, objective provisions we will be able to find a situation where the improved backstop is acceptable.”

This might come as music to Mrs May’s ears as she prepares to head off to Salzburg today for an informal summit with her fellow EU leaders. Over dinner, she will try to sell them her Chequers Plan.

The main ingredient in her argument will be the political reality that if Brussels does not bend a little, then the fudged deal she returns to Westminster with will be rejected by MPs and this will lead to a no-deal, which will be very damaging not just to the UK but to the EU as well.

Pre-summit activity gathered momentrum yesterday.

In London, the PM was hosting Manfred Weber, leader of the EPP - the main centre-right group in the European Parliament - in Downing Street.

They agreed that parliaments in Strasbourg and Westminster should be able to vote on a "precise plan" for the future UK-EU relationship after Brexit.

A Downing Street spokesman noted: "On Brexit, Weber recognised that the Chequers proposals were a step forward and stressed the priority the European Parliament placed on resolving questions relating to the border between Ireland and Northern Ireland, as well as to maintaining the integrity of the single market.”

In Paris, Emmanuel Macron was hosting Donald Tusk, the European Council President, who took to social media to warn that a no-deal would be a “catastrophe”.

The lunch with Mr Tusk followed 24 hours after talks with Sebastian Kurz, the Austrian Chancellor.

A source at the Elysee Palace accused Britain of putting the cart before the horse by moving on to the framework of the future relationship with the EU, even though the divorce itself had not been concluded.

“It’s a bit like sharing child care and the house before the divorce has been registered,” he said.

But if Mr Barnier is right about October, then the next four weeks will determine Britain’s future for a generation and tonight’s cordon bleu dinner will be the most important of Mrs May’s life.