Brexit High Court hearing: does the UK government need the approval of Parliament before it can invoke Article 50?

Today, the High Court has started hearing arguments on whether the UK government can go-it-alone and trigger Article 50 of the Lisbon Treaty – the legal mechanism to commence departure from the EU – without first seeking the approval of Parliament.

Opening the case, Lord Pannick QC for the lead claimant emphasised that the challenge was not about whether or not the UK should leave the EU, but whether the government has the legal power to trigger Article 50, with the inevitable consequences that follow, without an Act of Parliament. In his words “The notification is the pulling of the trigger and once pulled the bullet hits the target.”

The outcome of the case could have profound consequences for the government’s Brexit timetable, announced at the Conservative Party conference earlier this month (and discussed in our note here). That current timetable would see Article 50 triggered by the end of March 2017, meaning that we would expect (although see below) the UK to leave the EU in the spring of 2019.

The case is listed for two days and the court’s decision is expected within a matter of weeks.

If Parliamentary approval is not required

Should the court decide in favour of the government and hold that it can – subject to any appeal of the court’s decision – proceed to invoke Article 50 without first obtaining the approval of Parliament, then, on the basis of the government’s timetable, the UK would invoke Article 50 by the end of March 2017.

By triggering Article 50, the government will commence the two year period for negotiation of the terms of Britain’s exit from the EU. This negotiation period can only be extended with the consent of all EU Member States.

If Parliamentary approval is required

Should the court decide against the government and hold that it must obtain the approval of Parliament before invoking Article 50, then the key question is an obvious one: would Parliament give that consent?

On the one hand, MPs, regardless of their pre-referendum stance, might be reluctant to block the triggering of Article 50, given the referendum result. If Parliament is willing, it should be possible to secure the requisite Act of Parliament in readiness for the government’s March 2017 deadline.

On the other hand, the requirement for parliamentary approval may open the door to a debate followed by a vote on what the terms of Brexit should be and/or what the government’s negotiating position should be – before giving notice under Article 50. This could be difficult for the government for a variety of reasons. Indeed, it may even result in a General Election being called.

Uncertainty prevails

It may be some time yet before the legal position is fully clarified. It is widely expected that, whatever the decision of the High Court, the losing party will appeal the case to the Supreme Court, which would have the final say on this question of authority to trigger Article 50. The decision of the Supreme Court could be given by the end of the year.

For more on the potential consequences of Brexit for businesses, see our dedicated Brexit hub.