Key takeaways

• By a majority of 8-3, the UK Supreme Court has ruled that an Act of the UK Parliament is required before the UK government can notify the EU of the UK’s intention to withdraw from the EU by giving notice pursuant to Article 50 of the Treaty on European Union.
• The form and length of the legislation is entirely a matter for Parliament and the consent of the Northern Irish, Scottish and Welsh legislatures is not required before the relevant Act of the UK Parliament is passed.
• The UK government has announced that, despite the judgment, it still intends to invoke Article 50 by 31 March 2017. It is unclear whether this deadline remains realistic.
• It also remains unclear whether the UK government could revoke the Article 50 notice once issued to halt the withdrawal process; however, the government’s working assumption appears to be that it could not.