The Supreme Court has ruled by 8 votes to 3 that Parliament must vote on whether the government can start Brexit. This means Theresa May can't begin negotiations with the EU until she receives backing from her MPs and peers.
"The government cannot trigger article 50 without Parliament authorising that course," Lord Neuberger told the court in London on Tuesday morning.
He added that while government has the power to change the EU treaty, it can't do that if it will affect people's rights.
"The fact that withdrawal from the EU would remove some existing domestic rights of UK residents also renders it impermissible for the government to withdraw from the EU Treaties without prior Parliamentary authority," the court's judgement confirmed.
This result will not overturn the referendum result, though. Instead, it will give Parliament a say in what happens as the Prime Minister will need the consent of Parliament before formal talks on Brexit can begin. The BBC reports that this is expected to happen in time for the Theresa May's deadline to trigger Article 50 and begin the two-year negotiation process to leave the EU on 31 March.
"The British people voted to leave the EU, and the government will deliver on their verdict - triggering Article 50 as planned - by the end of March," a spokesperson for the government said following the court's decision. "Today's ruling does nothing to change that."
The reaction to the news has been mixed. Attorney General Jeremy Wright said "the government is disappointed with the outcome" of the judgement, but it will do everything it can "to comply with it."
Meanwhile, it's a triumph for Gina Miller, who challenged the government's presumption that it had the right to trigger Article 50. After the result, the philanthropist said she had been shocked by the abuse she had received "for simply bringing and asking a legitimate question". Many have been quick to praise Miller for her courage and influence.
A full summary of the Supreme Court's Brexit ruling can be viewed at supremecourt.uk
