The High Court has ruled that the government does not have the power to trigger Article 50 without seeking approval from MPs.
The government has said it will appeal the decision in the Surpreme Court.
The Lord Chief Justice ruled that the government’s arguments are “contrary to fundamental constitutional principles of the sovereignty of parliament”.
Adding: “The court does not accept the argument put forward by the government. There is nothing in the text of the 1972 Act to support it.”
Speaking moments after Lord Chief Justice Lord Thomas, delivered the ruling Development Secretary informed the House of Commons that the government would appeal in the Supreme Court.
If the Supreme Court upholds the High Court’s ruling the British government’s plans for exiting the E.U. could be thrown into disaray.
“The Government is disappointed by the Court’s judgment. The country voted to leave the European Union in a referendum approved by Act of Parliament. And the Government is determined to respect the result of the referendum,” said a government spokesperson.
Labour leader Jeremy Corbyn said: “This ruling underlines the need for the Government to bring its negotiating terms to Parliament without delay.
“Labour respects the decision of the British people to leave the European Union. But there must be transparency and accountability to parliament on the terms of Brexit. Labour will be pressing the case for a Brexit that works for Britain, putting jobs, living standards and the economy first.”