The U.K. government introduced Thursday an EU withdrawal bill that aims to convert the bloc’s law into British law, but already some of what has been left out of the measure has prompted angry criticism from opposition parties.

The aim of the measure is to ensure that the EU’s rules, which the U.K., as a member of the bloc, must follow, continue to apply after Brexit goes into effect in about two years. In effect, it will repeal the European Communities Act 1972, the law that brought the U.K. into what became the EU, and because the bloc’s rules would become U.K. laws, British lawmakers would have the power to change them.

“It is one of the most significant pieces of legislation that has ever passed through parliament and is a major milestone in the process of our withdrawal from the European Union,” David Davis, the Brexit minister, said.

But before debate begins on the bill this fall, it must gather the support of lawmakers. Prime Minister Theresa May heads a minority government with the support of the Democratic Unionist Party, the protestant party from Northern Ireland, and judging by the reaction from the opposition Labour and Liberal Democrats, she might have trouble gathering broad support for the measure.

At issue is the fact the EU withdrawal bill does not transform the EU charter of fundamental rights into U.K. law. Also, May’s government says upon Brexit, the U.K. will leave both Euratom, the bloc’s nuclear body, as well as the European Court of Justice.

Inclusion of the charter of fundamental rights is one of six issues Keir Starmer, the Labour leader in charge of Brexit, has put at the center of his party’s support of the withdrawal bill. The Liberal Democrats also want it included. But the U.K. government says the charter doesn’t need to be explicitly included.

“The charter of fundamental rights is a cornerstone of what makes Britain what we are,” Tim Farron, the outgoing leader of the Liberal Democrats, said. “I cannot understand what issue the government have with it.”

Membership of Euratom is another pivotal issue—but this one for Conservative lawmakers. They want the U.K. to remain in the body, but the government argues that the EU says the U.K. can’t leave the bloc and remain in the nuclear organization. The government’s position that the European Court of Justice should be unable to rule on U.K. cases is at odds with the EU’s position that the court should have jurisdiction over those cases that were filed before the U.K. leaves the bloc. Both these positions were laid out in policy papers issued this week.

May’s government also faced pushback Thursday over the withdrawal bill from the Scottish and Welsh governments, which argued the measure returns the EU’s powers “solely to the UK government and parliament, and imposes new restrictions on the Scottish parliament and national assembly for Wales.” They said they would block the bill unless the government makes major changes to it.