Prime Minister Theresa May must give parliament a vote before she can formally start Britain's exit from the European Union, the UK Supreme Court ruled on Tuesday, giving lawmakers who oppose her Brexit plans a shot at amending them.
A "straightforward" bill will now be rushed to parliament within days, the government said after the country's highest judicial body decided May could not use executive powers known as "royal prerogative" to invoke Article 50 of the EU's Lisbon Treaty and begin two years of divorce talks.
However, the judges did remove one major potential obstacle for the government, saying May did not need the approval of Britain's devolved assemblies in Scotland, Wales and Northern Ireland before triggering Brexit.
"We will within days introduce legislation to give the government the legal power to trigger Article 50," Brexit minister David Davis told parliament. "This will be the most straightforward bill possible to give effect to the decision of the people and respect the Supreme Court's judgment."
May has said she intends to invoke Article 50 before the end of March but the ruling means the Brexit process is now open to scrutiny from lawmakers, the majority of whom had wanted to stay in the EU.
However, the main opposition Labour Party has said it would not block Brexit although it would try to amend the legislation.