Article 50 of the Treaty on European Union – Q&A What is Article 50? Article 50 of the Treaty on European Union sets out the procedure for a Member State to withdraw from the European Union, if it should wish to do so. It was first introduced by the Lisbon Treaty in 2007. How does a Member State trigger Article 50? A Member State must notify the European Council of its intention to leave. There are no particular requirements regarding the form. What happens...