In early October, Prime Minister Theresa May announced plans to trigger Article 50 of the Lisbon Treaty before the end of March 2017, which would start the clock on the 2 year process of the U.K. leaving the European Union. However, a British high court has now ruled that the government must allow Parliament to approve the country’s departure from the E.U. While this decision will not stop Brexit, it is likely to slow the process, as May must now seek Parliament’s approval before starting the process of leaving the E.U. rather than waiting till after the 2-year process has been concluded. May has vowed to appeal this ruling to the British Supreme Court.
It should be noted that the decision rests on the holding that “The most fundamental rule of the U.K. Constitution is that Parliament is sovereign and can make or unmake any law it chooses.” This is the same argument made by those who wished to leave the E.U. in the first place.
The government claimed in its argument that under residual powers of royal prerogative, which cover international treaty-making, it had the power to invoke Article 50 without a vote in Parliament. This argument did not appear to hold water for the court who held that invoking Article 50 without the consent of Parliament would be a violation of the 1972 European Communities Act, a law that incorporates European laws into the British legal system and that provides that only Parliament has the power to invoke clauses like Article 50.
The decision is an interesting piece of constitutional law for British legal scholars. For more information on Brexit, please look at our U.K. research guide. For information on British constitutional law, search our catalog for books and articles that will give you a more in-depth appreciation for how the U.K. handles constitutional issues without having a written constitution. As always, we are available for research consultations and at the reference desks or via chat.