European Commission president Jean-Claude Juncker has dealt a further blow to Theresa May’s hopes of getting her Brexit deal through the Commons, saying it is the "best deal possible" with "no room whatsoever for renegotiation".
Mr Juncker confirmed he would meet the Prime Minister in Brussels on Tuesday evening following her talks with Dutch Prime Minister Mark Rutte and German Chancellor Angela Merkel.
But speaking in the European Parliament, he offered little hope of a breakthrough, saying:"I will see Mrs May this evening and I have to say here in the Parliament, as I did say before in this Parliament, the deal we have achieved is the best deal possible - it is the only deal possible."
MEPs applauded as Mr Juncker said: "There is no room whatsoever for renegotiation, but of course there is room if used intelligently, there is room enough to give further clarifications and further interpretations without opening the Withdrawal Agreement. "This will not happen: everyone has to note that the Withdrawal Agreement will not be reopened."
He said earlier that Brexit would a "surprise guest" at a European Council summit later this week, adding: "I'm surprised because we had reached an agreement on the 25th November together with the Government of the United Kingdom.
"Notwithstanding that, it would appear that there are problems right at the end of the road."
European governments echoed that message, with Greece's Europe minister George Katrougkalos saying "the ball is in the UK's court", and France's Europe minister Nathalie Loiseau warning the EU was preparing for a no-deal Brexit.
"We're very much concerned about postponement of the vote," Ms Loiseau said. "We've done a lot to help UK. This is only possible agreement and we've done a lot of concessions to reach it. We have to stand ready for a no deal and we're preparing for it."
Commons leader Andrea Leadsom suggested that Mrs May was seeking changes that would give Parliament an additional "democratic ability to decide", with MPs voting every year to decide on whether to stay in the controversial Irish border backstop.
She told the BBC’s Today programme: "That might include an addendum to the Withdrawal Agreement that sets out that Parliament will vote prior to going into a backstop, should that prove necessary, and potentially that the EU parliament and UK parliament must vote every year thereafter to provide that legitimacy for the UK to stay in the backstop, should that prove necessary.
"So there are plenty of options for the PM to talk to the EU about that don't involve reopening the Withdrawal Agreement, but that would provide the legal text as a part of the Withdrawal Agreement, through perhaps an addendum."
Ms Leadsom highlighted negotiations with Greece at the height of its crisis as an example of why it might still be possible to get additional concessions from Brussels.
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She said: "The EU is always in a position where it negotiates at the last possible moment.
"I think it would be very clear to colleagues, friends and neighbours in Europe, as well as the UK, that the deal as it stood was not going to get through the UK parliament.
"If we want to avoid a no-deal Brexit next March we need to go back to the drawing board to ensure that UK parliament has that democratic capability that it is demanding, quite rightly.
"That is why the Prime Minister is right to do this."