UK Prime Minister Theresa May emerged from a late-night meeting with European Commission President Jean-Claude Juncker claiming to have won important concessions to sweeten her Brexit deal just before MPs vote on it.

But at a news conference, Juncker conceded the EU had not agreed to the prime minister's central demand, and instead the two leaders negotiated a legal add-on to the Brexit deal which emphasising the temporary nature of the Irish backstop, which keeps the border between Ireland and Northern Ireland open while a new trade regimen is hammered out.  Juncker said it "complements" the withdrawal deal that May had already negotiated "without reopening it".

Ms. May insisted, "What we have secured is very clearly that the backstop cannot be indefinite, cannot become permanent.  It is temporary if it is the case that we were ever to get into the backstop." 

Labour leader Jeremy Corbyn said the deal contained nothing new of any consequence and urged MPs to vote against it.

"This evening's agreement with the European Commission does not contain anything approaching the changes Theresa May promised Parliament, and whipped her MPs to vote for," Corbyn said.  "Since her Brexit deal was so overwhelmingly rejected, the prime minister has recklessly run down the clock, failed to effectively negotiate with the EU and refused to find common ground for a deal Parliament could support."

The UK Parliament will begin debate on the changed when Tuesday rolls around to London.  The Brexit is scheduled to happen on 29 March, ready or not.