The Government has lost its historic battle in the Supreme Court over Brexit.
The highest court in the land rejected an appeal by ministers against a High Court judgment blocking their decision to begin Britain's exit from the European Union without Parliament having a say.
Supreme Court justices ruled, by a majority of eight to three, that Prime Minister Theresa May cannot lawfully bypass MPs and peers by using the royal prerogative to trigger Article 50 of the Lisbon Treaty and start the two-year process of negotiating the UK's divorce from its EU partners.
The ruling is a blow to Mrs May, who has repeatedly said she intends to trigger Article 50 by the end of March following the clear majority in favour of Brexit in the June 2016 referendum.
It was won by a wide-ranging group of anti-Article 50 campaigners led by investment manager Gina Miller, 51, and hairdresser Deir Dos Santos.
Supreme Court President Lord Neuberger said: "By a majority of eight to three, the Supreme Court today rules that the Government cannot trigger Article 50 without an Act of Parliament authorising it to do so."
Attorney General Jeremy Wright said the Government will do "all that is necessary" to implement a ruling of the Supreme Court that Parliament must give its approval to trigger the process of leaving the EU.
Mr Wright said the Government was "disappointed" by the final decision in its historic battle over who has the right to authorise the start of withdrawal negotiations under Article 50 of the EU treaties.
But he said that ministers will comply with the ruling, which effectively means that MPs must be given a vote on Article 50.
North East MEP and UKIP’s Constitutional Affairs spokesman Jonathan Arnott said,:”I am disappointed by the outcome of this case. There were strong legal arguments put forward on both sides, and ultimately I had hoped that the government's case would prevail because it would have reduced the risk of even greater delay to the British people's decision to leave the European Union.
"Nevertheless, the ruling has now been made. In the United Kingdom, when something goes against us - an election, a referendum, the final process in a legal case - we accept the result and move on. That is the nature of living in a democracy. I fully accept that this result has gone against my views, and now it is the responsibility of our Westminster Parliament to enact the will of the British people and get us out of the European Union.
"Just as I must accept the result of this court case, so too must our MPs and Lords accept the result of the referendum. Exactly seven months on from the declaration of the referendum result, we are still waiting for the decision of the people to be enacted. I call upon Parliament now to pass legislation for the United Kingdom to leave the European Union as a matter of extreme urgency. The democratically-expressed will of the British people can be frustrated no longer,” said Mr Arnott, North East MEP.