Britain's most senior judges have ruled Theresa May does NOT have the power to trigger the formal process for the UK's exit from the European Union.
Prime Minister Theresa May wanted to start the process of Britain leaving the European Union in March, and insists she and her ministers have the legal authority to trigger Article 50, which would begin the formal process.
Lord Neuberger, the President of the Supreme Court, said the government does have prerogative powers but "cannot exercise that power if it would thereby change UK laws unless it is authorised to do so by Parliament.”
“Today by a majority of 8 to 3 the Supreme Court rules that the government cannot trigger Article 50 without an Act of Parliament.”
He added the case "has nothing to do with whether the UK should exit from the EU",
Businesswoman Gina Miller led a consortium of pro-EU figures in a legal bid to demand MPs be allowed to scrutinise and vote on Article 50.
In an unprecedented move, all 11 Supreme Court justices sat as a panel to hear the appeal.
Although the Government lost the challenge, the justices unanimously ruled that there was need to consult with the devolved powers in Scotland, Wales and Northern Ireland.
In a statement released immediately after the ruling, Labour leader Jeremy Corbyn said his party would not "frustrate the process for invoking Article 50" but would seek to amend the Government's bill.
Attorney General Jeremy Wright has said the Government is "disappointed" by the Supreme Court ruling but will comply with it.
Gina Miller - the main complainant - said the case “went to the very heart of our constitution”.
“No Prime Minister, no government, can expect to be unanswerable or unchallenged. Parliament alone is sovereign.
“This ruling today means MPs we have elected will rightly have the opportunity to bring their invaluable experience to bear”.
She said Britons are “lucky” to have the right to hold government to account.
“I have therefore been shocked at the levels of personal abuse I have received from many quarters... for simply asking a legitimate question.
“I sincerely hope, going forward, that people who stand in positions of power and profile are much quicker in condemning those who cross the lines of common decency and respect.”