Although it would seem that the process for invoking Article 50 should be straightforward, a legal case was initiated to determine whether the Government can use Royal Prerogative Powers to start the process of leaving the EU.
Gina Miller engaged the City law firm Mishcon de Reya to challenge the authority of the British Government to invoke Article 50 of the Treaty on European Union using prerogative powers, arguing that only Parliament can take away rights that Parliament has granted.
After a hearing on 03 November 2016, the High Court of Justice ruled that Theresa May cannot use the Royal Prerogative Powers to invoke Article 50 and begin the process for withdrawal from the EU and she needs prior Parliamentary approval.
The Government decided to appeal the High Court’s decision and took the appeal directly to the Supreme Court.
The Supreme Court is the final court of appeal in the UK for civil cases, and for criminal cases from England, Wales and Northern Ireland. It hears cases of the greatest public or constitutional importance affecting the whole population.
The appeal hearing was held from 5-8 December 2016 with the decision to be issued in January 2017.
Details of the case and proceedings can be found at
The judgement by the Supreme Court was issued on 24 Jan 2017. The Secretary of State’s appeal was dismissed by a majority of 8-3. In a joint judgement of the majority, the Supreme Court holds that an Act of Parliament is required to authorise ministers to give Notice of the decision of the UK to withdraw from the European Union.
The judgement documents are available at:
A useful article, interpreting details of the judgement by Robert Craig: Miller Supreme Court Case Summary can be found at
The Supreme Court decided that the Government is not obliged to consult with the UK’s devolved assemblies before triggering Article 50 and also ruled that once Article 50 is triggered, it cannot be reversed.
The form that the legislation should take was not defined and is entirely a matter for Parliament but Parliament will need to pass a new bill that gives Government the authority to trigger Article 50.
A statement, following the ruling, from Number 10 added :
The British people voted to leave the EU, and the Government will deliver on their verdict – triggering Article 50, as planned, by the end of March. Today’s ruling does nothing to change that.
It’s important to remember that Parliament backed the referendum by a margin of six to one and has already indicated its support for getting on with the process of exit to the timetable we have set out.
We respect the Supreme Court’s decision, and will set out our next steps to Parliament shortly.
Opposition leader Jeremy Corbyn reacted to the judgment by saying that his party will not seek to frustrate the will of the British people, but did say that “Labour will seek to amend the Article 50 Bill to prevent Conservatives using Brexit to turn Britain into a bargain basement tax haven.”