EU chief Michel Barnier tonight unveiled an 'offer' to the UK on Brexit just four days before a crucial vote.
The Brussels chief negotiator took the unprecedented step of publicly tweeting his plan for a compromise on the Irish backstop.
Theresa May has for weeks being trying to rework the backstop - a clause in the 585-page Brexit deal that could trap the UK under EU customs rules.
She wanted either a way to quit the backstop, a time limit, or "alternative arrangements" to replace it.
Tonight Mr Barnier said the EU would commit to letting the UK exit the backstop - but only one part of it, a shared customs union with the EU.
That means the other provisions would have to stay - a move critics say will divide Northern Ireland from the rest of the UK.
Furious Brexit Secretary Stephen Barclay hit back on Twitter within minutes, tweeting: "With a very real deadline looming, now is not the time to rerun old arguments.
"The UK has put forward clear new proposals. We now need to agree a balanced solution that can work for both sides."
