A Northern Irish judge rejected a pair of challenges to the Brexit process, removing at least one obstacle to U.K. Prime Minister Theresa May’s plan to begin severing ties with the European Union by the end of March.

Justice Paul Maguire said on Friday that it was beyond the power of the Belfast court to interfere in how the government triggers Article 50, the notice of departure from the EU. He dismissed claims related to lawmakers’ votes and the Good Friday Peace accord in Ireland.

“The actual notification does not, in itself, alter the law of the U.K.,” Judge Maguire said in his decision. “Rather, it is the beginning of a process.” When laws do have to be changed, parliament will necessarily be involved, he said.

The decision in Belfast comes as a panel of three senior judges in London considers a similar case demanding a parliamentary vote before May invokes Article 50 of the Lisbon Treaty. It is likely both of the cases will be swiftly appealed to the U.K. Supreme Court for another hearing.

Investors have looked to the lawsuits to delay the move toward Brexit amid concerns that the prime minister is prioritizing immigration controls over safeguards for trade and banking. The June 23 referendum vote has caused the pound to lose 18 percent of its value — more than any other major currency — over fears that whatever deal emerges from negotiations between May and the EU will leave the country worse off.

The pound was 0.3 percent weaker at $1.2128 as of 11:48 a.m. London time.

“We welcome the court’s judgment this morning,” Prime Minister Theresa May’s spokesman, Greg Swift, told reporters in London on Friday. “We can proceed to trigger Article 50 as planned.”

Northern Ireland Vote

The residents of Northern Ireland — like those in Scotland — voted to remain in the EU during the non-binding referendum, which the “Leave” campaign won by a 52 percent to 48 percent across the U.K.

The activist and group of politicians bringing the Belfast lawsuit alleged that it would be illegal for May to unilaterally start the exit without lawmakers weighing in. In addition, they argued the shared border with Ireland and EU funds provided to victims of terrorist violence complicate the decision to exit.

Raymond McCord, a campaigner for victims of the Northern Irish conflict who brought the case, said outside court that he was disappointed with the decision. “Without a doubt we’ll be going to the Supreme Court in London. The judge has left the door open.”

May, originally a “Remain” supporter, has pledged to follow through on the voters’ will, and said she will reach the best agreement possible to restrict immigration to the U.K. while keeping close economic ties, a goal that EU officials have said will be difficult.

London Challenge

The London legal challenge, brought by a finance entrepreneur, a hairdresser and other claimants, sought a court ruling that it would be illegal for the government to invoke Article 50 without first consulting Parliament, a move that would likely delay Brexit.

The London and Belfast cases will both ultimately be decided by the U.K. Supreme Court, said Guy Lougher, a lawyer at Pinsent Masons in London who is a member of the Law Society of Ireland. The central issue in both cases is the role of Parliament, he said.

“If prior parliamentary approval is required before Article 50 can be triggered, there is a real risk that the necessary majority may not be forthcoming,” Lougher said before the ruling. “The stakes are very high.” And the Belfast “judgment is not the end of the matter.”