Updated 10 October
Scotland's Court of Session (Inner House) has ruled that it can make a reference to the Court of Justice of the European Union on the question of whether notification under Article 50 of the Treaty on European Union (TEU) may be unilaterally withdrawn by the State which gave the notice. Government arguments to the contrary were dismissed.
Any Wightman MSP v Secretary of State for Exiting the EU  CSIH 62
who include members of the Scottish, United Kingdom and European Parliaments, seek a declarator specifying: “whether, when and how the notification...can unilaterally be revoked”. The legal question, which the petitioners wish answered definitively, is whether the notification can be revoked in advance of the expiry of the two year period; with the effect that the UK would remain in the EU. The petitioners maintain that such an answer can only be given by the Court of Justice of the EU (CJEU). They therefore seek a reference to the CJEU for a preliminary ruling under Article 267 of the Treaty on the Functioning of the EU.
A relatively short reference has been drafted by the court and is appended to the judgment. The court will direct the parties to provide any submissions on the draft in writing within 14 days. It will then adjust the reference before transmission to the CJEU.
It was of passing interest to note para 30 of the judgment - "References by the Scottish courts to the CJEU have been rare. The Court of Session has been anxious, whenever possible, to resolve disputes which involve aspects of EU law without troubling the CJEU. Only about ten references have emerged from Scotland in some 45years .... "
As ever, there is the bucket of cold water ! (1) Presumably, it is open to the UK government to appeal this decision to the Supreme Court of the UK. (2) If the reference is made, the CJEU may decide that the reference is just an attempt to obtain an advisory opinion. (3) The CJEU may decide that the notification may not be withdrawn.
On any view, the reference should clarify what has been an underlying issue demanding an answer and may assist politicians in any voting on this matter in Parliament.
The drafting of Article 50 ought to have addressed whether a notification could be withdrawn. The fact that it is silent on the point led to a view that notification could not be withdrawn.
Law and Lawyers 23 July 2017
Law and Lawyers 7 February 2018
The Guardian 21 September - Jolyon Maugham QC - Today's ruling shows the triggering of Article 50 can be reversed
Update 10 October:
The CJEU has received the reference - see HERE. The case number is Case C-621/18 and a request for an expedited hearing has been granted with the court hearing set for 27 November 2018 - BBC News 5 October.
the Art 50 notification may be unilaterally withdrawn was not answered
in the Miller / Dos Santos case because that litigation proceeded on a
basis agreed by the parties that the government would not revoke the
notice. This was criticised - e.g. Eutopia Law - Miller judgment breaches UKSC duties under EU law
For further discussion about unilateral withdrawal see this previous post 23 July 2017
and also see Professor Steve Peers at Eulaw Analysis 18 January 2018 and European Law Blog 24 September 2018.