Jean-Claude Juncker warns MPs there is 'no third chance' as they prepare to vote on Brexit deal

European Commission President Jean-Claude Juncker has warned MPs they will get "no third chance" to make Brexit happen after Theresa May agreed a batch of last-minute changes to her EU deal.

Speaking after crunch talks in Strasbourg, the EU chief urged MPs to back the "improved" agreement in the second meaningul vote on Tuesday evening or risk scuppering the Brexit process entirely.

"Let us be crystal clear about the choice - it is this deal or Brexit might not happen at all," he said.

And he warned MPs: "There will be no new negotiations. It is this. In politics, sometimes you get a second chance.

"It is what we do with the second chance that counts. Because there will be no third chance.

"There will be no further interpretation of the interpretations and no further assurances on the reassurances."

The uncompromising message comes just hours before MPs again cast their verdict on May's deal in the House of Commons, after overwhelmingly rejecting it by 230 votes in January.

Speaking before flying back to London, the Prime Minister talked up two new documents agreed between Britain and the EU to bolster her Brexit deal and said she had delivered on her promises to win fresh guarantees that the Northern Ireland backstop will be temporary.

"The deal that MPs voted on in January was not strong enough in making that clear – and legally binding changes were needed to set that right," she said.

"Today we have agreed them."

The two sides have signed off on a "joint legally binding instrument", which Mrs May said had "comparable legal weight" to the Brexit agreement itself and would "guarantee that the EU cannot act with the intent of applying the backstop indefinitely".

Meanwhile a joint statement commits both sides to replacing the backstop with "alternative arrangements" by the end of December 2020.

Brexiteer Tories and the Democratic Unionist Party, who May relies on for her Commons majority, had demanded assurances that Britain would not be locked in the backstop, which seeks to avoid a hard border in Northern Ireland.

Reacting to the changes, the DUP's Westminster leader Nigel Dodds told MPs: "All of this will need to be taken together and analysed very carefully because we are speaking at the moment without having had sight of the precise text."

Meanwhile Jacob Rees-Mogg, leader of the European Research group of Brexiteeer Tory backbenchers, said it was "too early to tell definitively but it's clearly a step in the right direction"