Prime Minister Theresa May is preparing to reject the European Union’s draft Brexit deal when it’s published Wednesday, a senior official said, as her government steps up its fight with the bloc over the terms of Britain’s departure.

With just three weeks left to agree on the Brexit transition phase, the EU will unveil a legal text that’s likely to infuriate euroskeptics in May’s Conservative government, piling further pressure on the premier at a critical time.

According to the senior official, May will take on the EU over two of its key proposals that are unacceptable to her government. These are allowing the European Court of Justice to oversee the final deal, and arranging a separate trading regime for Northern Ireland—which, although it could avoid a “hard border” with Ireland, would impose new barriers with mainland Britain.

Almost a year in since May triggered the U.K.’s withdrawal from the 28-nation club, talks have yet to begin on what kind of trade accord will follow.

Time is running out to limit the damage this ongoing uncertainty will cause to British businesses, who want a status quo transitional phase to be agreed by the end of March at the latest, to help them prepare and adapt when Britain leaves in March 2019. Yet key conflicts remain unresolved between the U.K. and the EU negotiating teams.

“I maintain the evaluation that I gave you three weeks ago, which is that in light of these divergences, that we haven’t achieved the transition,” EU chief negotiator Michel Barnier said Tuesday. His remarks raise the prospect that the deal will miss its crucial end-March deadline.

EU’s Draft Text

The EU says the transition period should last only until the end of 2020, but the U.K. has suggested it should be longer.

The transition is one of several issues to be included in the draft text of the Brexit treaty drawn up by the EU that will be published Wednesday.

The 100-page document will also include options for the Irish border, controversially focusing on May’s worst-case plan: alignment of regulations between the U.K. and the Republic of Ireland. This was originally proposed in December as a fall-back option if a broader trade agreement failed to maintain the frictionless border that exists now between Northern Ireland and the Republic.

On Friday, May will announce her own vision for the trade relationship she wants the U.K. to have with the EU, but the bloc’s leaders have already rejected the outline of the plan that has emerged so far.

May’s speech will be a high-wire act as Brexit is also endangering her own domestic position. Pro- and anti-Brexit rebels in her ruling Conservative Party are hemming her in just as the EU demands that she makes compromises on what the bloc says is an unrealistic, “cherry picking” approach to market access.

May’s working majority in Parliament is so slim that one false move could topple her. Pro-EU Conservatives are stepping up their campaign to maintain close ties to Europe, just as hardline Brexit backers are increasingly vociferous about cutting loose.

Eight Conservatives now back an amendment in Parliament that seeks to keep the U.K. in the customs union in an attempt to rewrite the government’s Brexit policy—and more could still add their names. Given the parliamentary arithmetic, even such small numbers could prove to be politically fatal.

May’s majority is made possible by 10 lawmakers of Northern Ireland’s Democratic Unionist Party, who are fighting to make sure that May’s pledges on avoiding a hard border on the island of Ireland don’t end up creating a new frontier between Northern Ireland and mainland Britain.