One of them is that Parliament must also hold a vote on the same. But British Prime Minister, Theresa May has moved to the high court to stop the voting by parliament.
She is arguing that it is unfair to the British people to make them carry out a referendum that would be so easily overruled by a parliamentary vote
The prime minister and the government are looking to enforce old monarch laws called royal prerogative to overturn the parliament from voting. The law state that the royal, in this case, the Prime Minister has Vito powers to pass laws without parliament voting.
But Brexit Secretary David Davis is adamant that the Supreme Court ruling will not affect anything. "Whatever the outcome of the Supreme Court appeals ... we intend to stick to the existing timetable for triggering talks," he said.
Britex has received massive opposition from many people, especially business people who argue that Britex would interfere with their freedom of movement. In essence, no law should interfere with any right, and there this argument won in a high court ruling. But the outcome of this victory is not clear at the moment.