European Union – 'Brexit'. Article 50 of the Treaty on European Union (TEU) had to be interpreted as meaning that, where a member state had notified the European Council, in accordance with that article, of its intention to withdraw from the EU, that article allowed that member state - for as long as a withdrawal agreement concluded between that member state and the EU had not entered into force or, if no such agreement had been concluded, for as long as the two-year period laid down in art 50(3), possibly extended in accordance with that paragraph, had not expired - to revoke that notification unilaterally, in an unequivocal and unconditional manner, by a notice addressed to the European Council in writing, after the member state concerned had taken the revocation decision in accordance with its constitutional requirements. The Court of Justice of the European Union so ruled in a preliminary ruling concerning the interpretation of art 50 TEU in proceedings regarding the possibility of unilaterally revoking the notification of the UK's intention to withdraw from the EU.