Theresa May and Jean-Claude Juncker have warned MPs contemplating voting down their Brexit deal that there is no Plan B and they should forget rejecting the UK-EU agreement in the hope of returning to Brussels to renegotiate a better one.

Both the Prime Minister and the European Commission President insisted the agreement on Britain’s withdrawal and the political declaration on a future trading partnership was the “only deal possible”.

Jeremy Hunt, the Foreign Secretary, also warned MPs: “If we turn this deal down, it is not automatically the case that Europeans will agree to negotiate a better deal."

On Monday, Mrs May will chair Cabinet to discuss with her senior colleagues how best to sell the deal to the nation before making a Commons statement on the special European Council meeting.

On Tuesday, the European Court of Justice will give its ruling on whether or not the UK Government can unilaterally terminate the Article 50 process and stop Brexit in its tracks.

After the leaders of the EU27 took just 38 minutes to endorse a deal that had taken more than 500 days to negotiate, Mr Juncker issued a stark message to MPs intent on trying to change it: "This is the best deal possible for Britain, this is the best deal possible for Europe. This is the only deal possible.

"Those who think by rejecting the deal that they would have a better deal will be disappointed in the first seconds after the rejection of this deal," added the Commission President.

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Leo Varadkar, the Irish Prime Minister, also stressed the point, declaring: "There isn't a Plan B. What's being put in front of EU parliament and House of Commons is a deal. Any other deal really only exists in people's imagination."

And Mark Rutte, the Dutch premier, added: "This is the deal on the table. I don't think there is anything more now."

Mrs May, who has said she will take her campaign to promote the EU28 deal up and down the country, echoed David Cameron’s remarks during the 2014 independence campaign, by saying she would argue for her Brexit plan “heart and soul”.

At a post-summit press conference the PM suggested the public was fed up of all the wrangling over Brexit and wanted to move on.

"It will be one of the most significant votes that Parliament has held for many years. On it will depend whether we move forward together into a brighter future or open the door to yet more division and uncertainty.

"The British people don't want to spend any more time arguing about Brexit. They want a good deal done that fulfils the vote and allows us to come together again as a country.

"I will take this deal back to the House of Commons, confident we have achieved the best deal available and full of optimism about the future of our country.

"In Parliament and beyond it, I will make the case for this deal with all my heart and I look forward to that campaign," she said.

Earlier, pressed on whether the Government could collapse if MPs rejected the deal, Mr Hunt acknowledged: "It's not possible to rule out anything."

Responding to the EU27 endorsement of the Brexit Plan, Jeremy Corbyn denounced it as a “bad deal” for Britain and confirmed Labour would be voting against the agreement.

"It is the result of a miserable failure of negotiation that leaves us with the worst of all worlds," declared the Labour leader.

In her Brussels press conference, the PM refused to be drawn on whether she would stand down if she lost the vote, despite being repeatedly pressed on the issue.

"I am focusing on ensuring that I make a case for this deal to MPs," she insisted.

Meanwhile, Mr Juncker expressed his sadness at Britain’s decision to leave the EU bloc but suggested that the post-Brexit relationship would remain a very close one.

Noting how "divorce is a tragic moment," the Commission President told reporters: "I don't think Britain will be a third country like other third countries are third countries. There is, between us, something which has the remainings of love."