LONDON, United Kingdom (AFP) – British Prime Minister Theresa May warned lawmakers on Sunday not to block Brexit, after the High Court ruled that she cannot start the process of leaving the European Union without parliament’s approval.

The Conservative government has said it will appeal Thursday’s court decision and May told EU leaders on Friday that she believes it has a strong case.

In a statement published ahead of a trade mission to India, May cautioned members of parliament against using the ruling to undermine the result of the June referendum.

“The result was clear. It was legitimate. MPs and peers who regret the referendum result need to accept what the people decided,” she said.

Supporters of Brexit responded angrily to the court’s decision, amid speculation that pro-European lawmakers would seek to water down the break with the EU and derail May’s plans to begin formal exit talks by the end of March.

“Now we need to turn our minds to how we get the best outcome for our country,” the prime minister said. 

“That means sticking to our plan and timetable, getting on with the work of developing our negotiating strategy and not putting all our cards on the table.

“That is not in our national interest and it won’t help us get the best deal for Britain.”

The High Court ruled that the government does not have the power to trigger Article 50 of the EU’s Lisbon Treaty, which would set off a two-year countdown to leaving the bloc, without the  prior approval of parliament.

May is expected to sign a host of commercial deals during her visit to India, her first trip outside Europe since taking over from David Cameron, who stepped down after the Brexit vote.