The political uncertainty surrounding the Brexit process has led to much speculation about the possibility of the UK withdrawing its Article 50 notice, to avoid a "no deal" scenario. At present, it is not clear whether this is legally possible, so it is significant that, at the end of September, a Scottish Court referred this issue to the ECJ (Wightman v Secretary of State for Exiting the European Union). The poor reaction to Theresa May's proposed Chequers plan, from the public and from EU leaders at the Salzburg Summit, make this decision all the more relevant.

The decision of the Scottish Court of Session, the highest court in Scotland, overturned an earlier ruling. The UK Government has applied for permission to appeal the Court of Session's decision to the Supreme Court and that application will be heard on 8 November. In the meantime, the ECJ referral will proceed.

Assuming that the referral is neither withdrawn nor stayed following the 8 November application, the likely outcome of the ECJ case, expected at the end of November, is uncertain, but the Scottish Court recognised the importance of the decision in providing an alternative for MPs faced with a difficult choice between what they may perceive to be a poor exit deal with the EU and no deal at all. In reaching its decision, the ECJ will need to grapple with complex questions of EU and international law, which are explored in more detail in our longer article here. Interestingly, Lord Kerr, who was involved in the drafting of Article 50, has himself said that it was always intended that Member States exercising their rights under Article 50 could change their minds.