The Supreme Court has dismissed the government’s appeal in a landmark case about Brexit, meaning Parliament will be required to give its approval before official talks on leaving the EU can begin.
The ruling is a significant, although not totally unexpected, setback for Theresa May.
What will the prime minister do next and what impact will the ruling have on the process of leaving the EU, following last year’s referendum vote?
The highest court in England and Wales has dismissed the government’s argument that it has the power to begin official Brexit negotiations with the rest of the EU without Parliament’s prior agreement.
By a margin of eight to three, the 11 justices upheld November’s High Court ruling which stated that it would be unlawful for the government to rely on executive powers known as the royal prerogative to implement the outcome of last year’s referendum.
But it said the precise form the legislation should take was “entirely a matter for Parliament”.