LEGALLY binding changes that could finally allow Britain to agree a Brexit deal emerged last night.

Cabinet Office minister David Lidington says legally binding changes that strengthen and improve the withdrawal agreement have been secured.

"Tonight we will be laying two new documents to the House - a joint legally binding instrument on the withdrawal agreement and a joint statement to supplement the political declaration," he said.

He says the documents provide "confirmation that the EU cannot trap the UK in the backstop indefinitely."

It comes after Theresa May set off to Strasbourg for last-minute Brexit talks with European Commission president Jean-Claude Juncker and was preparing to make a late night statement.

And it comes hours ahead of Tuesday's meaningful vote on the Withdrawal Agreement.

It was speculated that Ms May would make a unilateral statement from UK side on the backstop that the Prime Minister thinks will help attorney general Charles Cox to revise his legal opinion, given before the last vote on May’s deal, that the backstop could be in force “indefinitely”.

The prime minister's supporters hope she will be able to secure enough of a concession to get her deal through Parliament.

Joanna Cherry, the SNP's justice and home affairs spokesperson in the House of Commons tweeted in response to the proposed statement: "I'm hearing the UK government could be well on the road to getting enough to get their deal through @HouseofCommons. It won’t be with @theSNP support. Big decisions ahead for Scotland #indyref2."

HeraldScotland:

Discussions are focussing on changes to the so-called Irish Sea border backstop, the insurance policy in UK-EU Brexit negotiations to ensure there is no hard border in Ireland, that were expected to protect UK from bad faith by the EU in negotiations over the coming two years on a full agreement.

It is understood debate is about alternative arrangements either to replace the backstop or prevent it ever being needed.

But some observers question if anything can be agreed to guarantee that the backstop is not permanent.

But Dublin MEP Nessa Childers added: "General feeling in Strasbourg is that if there is a short meeting between May and Juncker with a statement at the end some class of a deal has been done. Then over to Westminster and decisions for Tories and Labour. "

Linda McAvan, the Labour MEP for Yorkshire & The Humber said: "Well Theresa May is here in Strasbourg - and possibly the Irish PM - to meet Juncker. Rumours (are) she’s going to ask for Brexit postponement until May 24 - day of European Parliament elections. Statement at 10pm UK time. Watch this space."

One theory suggests that the key to a breakthrough is a letter by European Council president Donald Tusk  and Juncker on January 14, which if turned into legally binding protocol could be grounds for Cox to change his opinion.

It says: "The European Commission can also confirm our shared understanding that the Withdrawal Agreement and the Protocol on Ireland/Northern Ireland: Do not affect or supersede the provisions of the Good Friday or Belfast Agreement of 10 April 1998 in any way whatsoever; they do not alter in any way the arrangements under Strand II of the 1998 Agreement in particular, whereby areas of North-South cooperation in areas within their respective competences are matters for the Northern Ireland Executive and Government of Ireland to determine."

That means that if the backstop were to become permanent, it would contradict the Good Friday Agreement as it would replace the Northern Ireland and Republic cooperation with a UK and EU construct. 

HeraldScotland: Jean-Claude Juncker

In theory, the UK could use this protocol with the withdrawal agreement to justify getting out of the backstop if it was seen to be becoming permanent.

Mrs May was also to meet Guy Verhofstadt, the European Parliment's Brexit coordinator, for talks on Monday evening.

Mrs May is likely to arrive in Strasbourg in mid-evening, and a statement to the Commons by Brexit Secretary Stephen Barclay has been put back to around 10pm.

Time is running out for any new assurances or clarifications to the deal which was resoundingly rejected by a 230-vote majority by MPs in January.

The Government must table its motion for Tuesday's debate by the end of the day, alongside the publication of any relevant documents.

MPs have also been promised that they will be shown any updated legal advice from Attorney General Geoffrey Cox before the debate begins.