Theresa May held “robust but constructive” talks with European Commission president Jean-Claude Juncker as she sought changes to her Brexit deal.

Mr Juncker underlined that the Withdrawal Agreement thrashed out between the EU and Mrs May would not be redrawn, but held open the possibility of adding “more ambitious” wording to a document setting out plans for the future relationship.

The Prime Minister is holding a series of meetings with EU leaders in Brussels as she seeks changes to the Irish backstop in an effort to get a deal through the House of Commons.

Following talks with Mr Juncker, a joint statement said: “The discussion was robust but constructive.

“Despite the challenges, the two leaders agreed that their teams should hold talks as to whether a way through can be found that would gain the broadest possible support in the UK Parliament and respect the guidelines agreed by the European Council.”

Brexit Secretary Stephen Barclay and EU chief negotiator Michel Barnier will meet next Monday, while Mr Juncker and Mrs May will have another meeting before the end of the month to take stock of the situation.

Mrs May set out MPs’ demands for a “legally binding change to the terms of the backstop”, while Mr Juncker “underlined that the EU27 will not reopen the Withdrawal Agreement”.

But he “expressed his openness to add wording to the Political Declaration” to be “more ambitious in terms of content and speed when it comes to the future relationship”.

In diplomatic statements, the description “robust” often indicates a heated row.

European Commission spokesman Margaritis Schinas said that the word was “something that both sides agreed was an accurate way to describe the tonality of the meeting”.

As Mrs May arrived in Brussels a protester waving a placard reading “Don’t crash out” leaped in front of the PM’s convoy as it arrived at the Commission’s Berlaymont HQ but was quickly whisked away.

The Prime Minister’s visit to Brussels follows the latest salvo in the war of words between the two sides.

The spat was triggered by European Council president Donald Tusk saying there was a “special place in hell” for those who pushed for Brexit without a plan.

David Lidington, who is effectively Mrs May’s deputy, said Mr Tusk’s comment “wasn’t the most brilliant diplomacy in the world”.

In Westminster, Labour leader Jeremy Corbyn wrote to the PM setting out five demands, including joining a customs union, that would need to be met for Labour to back the Government on Brexit.

Downing Street confirmed that Mr Corbyn’s letter had been received, and a spokeswoman added: “We will reply in due course. Our positions on many of the issues in the letter are well known. Our position on the backstop has not changed.”

The spokeswoman said that no further meeting between Mrs May and the Labour leader to discuss Brexit had been scheduled, but added that “her door is open”.

At the heart of the Brexit crisis is the backstop, which is intended to prevent the return of a hard border in Ireland, would see the UK continue to obey EU customs rules after a transition period if no wider trade deal had been reached.

(PA Graphics)
(PA Graphics)

Downing Street said that Mrs May is “open to different ways” of achieving her objectives on the backstop.

Mrs May was offered a chink of light by German Chancellor Angela Merkel, who again ruled out reopening the Withdrawal Agreement, but said she believed “solutions” could be found.

Speaking during a visit to Slovakia, Mrs Merkel said: “I think we can find solutions without reopening the Withdrawal Agreement. That is not on the agenda for us.”

The possibility of a “disruptive” Brexit is causing economic uncertainty in the EU, commission vice-president Valdis Dombrovskis said, as Brussels revealed its latest economic forecast.

The EU economy is expected to grow 1.5% in 2019, with the UK’s forecast at 1.3% – although this is a “purely technical assumption” based on a status quo relationship with Brussels.

Mr Dombrovskis said: “The possibility of a disruptive Brexit creates additional uncertainty.”

Meanwhile, the Daily Telegraph reported that Mrs May is seeking to delay another Commons “meaningful vote” on the Government’s Brexit stance until the end of February – just a month before the UK is scheduled to quit the EU on March 29.