A UK court ruled that the government can’t trigger negotiations to leave the European Union without a vote from Parliament, dealing a major blow to Prime Minister Theresa May’s plans.

The UK government said it was disappointed by the judgment and that it would appeal the ruling, which could force the government to get parliamentary approval to trigger Article 50, the formal mechanism that begins a two-year window for exit negotiations, The Wall Street Journal reported on Thursday.

If Parliament is allowed to vote on the trigger, lawmakers could influence her approach to Brexit and if a majority is opposed it could theoretically delay or even stop the process. May’s ruling Conservative Party is the largest party in Parliament, with a majority of 15 seats.

The pound surged more than 1% against the dollar following the decision.

“The country voted to leave the European Union in a referendum approved by act of Parliament,” a UK government spokesman said. “And the government is determined to respect the result of the referendum"

The Supreme Court is on standby to give an expedited hearing before a full bench of 11 judges early next month.

Source: MENA