On November 3, 2016, the High Court handed down potentially the U.K.’s most significant constitutional decision of the century. The Court determined that the Government cannot trigger Article 50 of the Lisbon Treaty without an Act of Parliament allowing it to do so. The Court has ruled that Parliament alone holds the power to enact the results of the U.K.’s referendum on Brexit, with the Lord Chief Justice reiterating the fundamental value of Parliament’s sovereignty in his delivery of the decision.

Last month, Prime Minister Theresa May declared her intention to trigger Article 50 by the end of March 2017, thereby beginning the process of Britain’s extraction from the European Union. This was met by some dissent. The court case which followed centered on the question of where the remit of the Royal prerogative ended, and Parliamentary power took over. In their submissions to the court, the claimants argued that to allow the Government to invoke Article 50 autonomously in the absence of Parliamentary permission would be contrary to the purpose of the European Communities Act 1972. The Government rebutted this through their submission that the passing of the EU Referendum Act signaled Parliament’s surrender of its role in Britain’s exit from the EU. Moreover, whilst the claimants focused on the non-binding and consultative nature of the referendum in June 2016, the Government took an opposite stance. The Government believed that the basis of the referendum was that the Government would implement its results, without any additional requirement of Parliamentary permission. Today’s decision in favor of Parliamentary sovereignty should enable MPs to hold the Government accountable for their negotiations and plans for Brexit.

Several questions have already arisen in the wake of the High Court’s decision, due to the very unique nature of this case. The heaviest question at hand seems to be how the Parliamentary consultation will be structured – will there be a straightforward yes or no vote, or does further, complicated legislation lurk on the horizon?

The case is being fast-tracked, with an appeal to be heard by the Supreme Court on December 7-8. We are monitoring the situation closely and will inform you of any updates as they unfold.