Advocate General Campos Sánchez-Bordona has published his Opinion on the request of the Inner House of the Court of Session for an Advisory Opinion from the CJEU as to whether or not a Member State that has notified the European Council of its intention to withdraw from the EU in accordance with Article 50 TEU may unilaterally revoke that notification and, if so, subject to what conditions: see Wightman, Reclaiming Motion by Andy Wightman MSP and Others Against Secretary of State for Exiting The European Union  ScotCS CSIH 62. The UK Government contends that the question referred for a preliminary ruling is inadmissible: it is hypothetical and merely theoretical because there is no indication that the UK Government or Parliament is going to revoke the notification of the intention to withdraw; however, he rejects that argument.
According to the Court’s press release, AG Campos Sánchez-Bordona considers that none of the conditions which, according to the Court’s case-law, govern whether a reference for a preliminary ruling should be declared inadmissible, are satisfied. He believes that the dispute is genuine and that the question is neither academic, premature nor superfluous, but has obvious practical importance and is essential in order to resolve the dispute.
In answer to the question from the Inner House, he proposes that the Court of Justice should declare that Article 50 TEU allows the unilateral revocation of the notification of the intention to withdraw from the EU, until such time as the withdrawal agreement is formally concluded, provided that the revocation has been decided upon in accordance with the Member State’s constitutional requirements, is formally notified to the European Council and does not involve an abusive practice.
The CJEU is not obliged to follow the Opinion of the Advocate General; in practice, however, the Court rarely takes the opposite view.