The High Court of Justice ruled on the 3rd November 2016 that the British government does not have the authority to proceed with the UK's exit from the European Union without the approval of Parliament. This decision may further complicate the complex process of exiting from the EU but will certainly not stop it.
A group of individuals led by a businesswoman, all in favour of remaining in the EU, brought this legal challenge before the High Court to answer a fundamental legal question about the powers that can be used by the Prime Minister and whether they can side-step parliament. The government's argument mainly resides in the fact that the decision was taken by the public in the referendum on 23rd June and that its executive power under the royal prerogative allows it to trigger Article 50 of the Lisbon Treaty.
Three senior judges ruled against this argument. They deemed that the British Government could not trigger Article 50 without first obtaining the formal agreement of the British Parliament. The UK's accession to the EU, voted by the British Parliament, has given citizens a wide range of rights, including freedom of movement within the EU, for instance. These rights can not be withheld from the British people without a new vote by Parliament. The referendum held in June had never been expected to "bind" Parliament to its outcome. It is therefore necessary to ask Parliament to vote on the matter. The president of the Court considered the judgment to be a "purely legal question": "The court is not concerned and expresses no view on the merits of a political exit from the European Union. "
The government appealed this decision and it will be heard by the Supreme Court on 7th and 8th of December this year. If the Supreme Court decides to confirm the decision, the government will have to go through Parliament to trigger Article 50.
Going through Parliament does not necessarily mean that Brexit will not happen. The majority of MPs voted in favor of remaining in the EU but the majority of their constituents voted for Brexit, so it may be argued they are unlikely to defy their constituents' wishes. The House of Lords, on the other hand, which is not an elected body, may have a different outcome. On a positive note, the introduction of a new bill would allow MPs to hold the UK government accountable and, above all, clarify the type of Brexit it intends to negotiate.
If there has to be a new bill that goes through both chambers stage by stage, it will be a long and uncertain fight for the government. This won't likely allow for Theresa May's original timetable which would have meant triggering article 50 by the end of March 2017.