A judicial review raised by members of the Scottish, UK and European Parliaments sought clarification on whether and how the UK’s notification to leave the EU under article 50 of the Treaty on the Functioning of the European Union (TFEU) could be “unilaterally revoked” before the two-year Brexit deadline on 29 March 2019, with the effect that the UK would remain in the EU.

At first instance, a judge declined the petitioners’ request to refer the issue to the CJEU for advice on European law, but three appeal judges have now reversed that decision.

The Lord President, Lord Carloway, sitting with Lord Menzies and Lord Drummond Young, heard that the petitioners, Andy Wightman MSP and others, were seeking a declarator specifying: “whether, when and how the notification…can unilaterally be revoked” – a legal question which could only be given by the Luxembourg-based Court of Justice.

In their draft reference to the CJEU, the judges ask: “Where, in accordance with Article 50 of the TEU, a Member State has notified the European Council of its intention to withdraw from the European Union, does EU law permit that notice to be revoked unilaterally by the notifying Member State; and, if so, subject to what conditions and with what effect relative to the Member State remaining within the EU?”

The Court of Session will consider the CJEU’s advice before issuing a final ruling.