Theresa May has left London for Strasbourg in a bid to secure a last minute change to her Brexit deal, ahead of a critical vote tomorrow.

Downing Street confirmed that the prime minister will meet Jean-Claude Juncker for talks following days of painstaking technical and political discussions.

In the late afternoon Number 10 insiders were still playing down any talk that a deal had been actually struck, saying only that the PM’s trip meant there are grounds for positive discussions.

It comes just 24 hours before a crunch vote in the commons, with eurosceptic MPs threatening to oppose the deal unless Ms May secures significant changes.

Earlier in the day Irish foreign minister Simon Coveney said: “The negotiations are ongoing. Many had hoped we would have clarity at this stage, particularly in advance of the vote tomorrow. We don’t yet.

“The British prime minister is travelling to Strasbourg this evening, I understand, to try to finalise an agreement, if that is possible, to be able to put that to a meaningful vote in Westminster tomorrow.”

Brexit secretary Stephen Barclay, who was party to recent political discussions with Brussels along side attorney general Geoffrey Cox, will accompany Ms May to the talks.

They and other officials are expected to land in Strasbourg at 8pm UK time, before going into a meeting with Commission president Mr Juncker. Photographers have been told to be ready for a 10pm press conference involving Ms May.

She must convince Tory Brexiteer MPs in the backbench European Research Group and her Northern Irish DUP partners in government that any change she secures allows the UK a legally-binding way out of the ‘Irish backstop’ arrangement currently set out in the withdrawal agreement.

The backstop comes into play if the EU and UK have failed to agree future trading arrangements by the end of 2020, thus keeping the Irish border open, but also locking the UK into a customs union with the EU on a potentially indefinite basis.

A key indicator of how successful her renegotiation of the withdrawal agreement has been, will be if Mr Cox is able to change his legal advice to the government relating to the indefinite nature of the backstop.

Members of the ERG have previously said that the backstop would have to be replaced altogether, something the EU will not agree to, raising questions as to wether any alterations made by negotiators will suffice.

Brexit minister Robin Walker confirms votes on no-deal and Article 50 extension this week if Theresa May's deal is rejected

Speaking earlier in the day Mark Francois said: “This isn’t just semantics. There’s a big difference between replacing something, and just tweaking it.

“And what the government have asked them, is to tweak it. What the commons, what the House of Commons, what parliament gave her a mandate to ask for, was to replace it. That’s what the House of Commons voted for.”

The prime minister’s de-facto deputy David Lidington is now set to make a commons statement on Brexit this evening, that could update MPs on any breakthrough.

Insiders said it could be possible that the statement is pushed back as late as 10pm, in order to allow Mr Lidington to be in the best position possible to inform the house.