Theresa May will urge the EU to help get her Brexit deal through the Commons by agreeing legally binding changes to the controversial backstop.
On Friday, she will say the EU’s actions will “have a big impact on the outcome” when MPs vote on it next week.
But Labour’s Sir Keir Starmer said it was now “clear” the PM “will not be able to deliver the changes she promised to her failed Brexit deal”.
The EU says the UK must come forward with new ideas to break the deadlock.
The UK is due to leave on 29 March.
Mrs May will visit workers in Grimsby, Lincolnshire, on Friday, days before the second “meaningful vote” in the Commons on the withdrawal deal she has negotiated with the EU.
She will tell them: “Just as MPs will face a big choice next week, the EU has to make a choice too.
“We are both participants in this process. It is in the European interest for the UK to leave with a deal.
“We are working with them but the decisions that the European Union makes over the next few days will have a big impact on the outcome of the vote.”
BBC political correspondent Ben Wright said making a public appeal to the EU for compromise just four days before the vote was an admission of how tough negotiations with the EU were proving.