As the Article 50 negotiations become increasingly fraught, you could be forgiven for not having noticed the court case which may have a crucial role to play in the outcome of the Brexit process. The case, started by various members of the Scottish, UK and European parliaments, seeks a declaration as to whether the Article 50 notification (the notice that started the formal process of leaving the EU) can unilaterally be revoked by the UK prior to 29 March 2019, when the UK is scheduled to leave the European Union. As various Parliamentary actors seek to have a meaningful vote on the terms of the ultimate deal (if one is agreed), the question of whether simply withdrawing the notice is possible is likely to have a big impact on whether pro-EU MPs seek to accept the deal (if the Article 50 notice cannot be withdrawn and the only alternative is a "no deal" Brexit) or, if withdrawal is not possible, reject the deal and seek to remain in the European Union.
The Scottish Court of Session ruled, in its judgment of 21 September 2018, that this matter should be referred to the ECJ for determination. On the basis that the date of the UK's departure from the EU is now fast approaching its was judged not to be an academic or premature question to ask whether it was possible legally to revoke the notification and remain in the EU. If it is found that the notice cannot be unilaterally revoked then any attempt to stay within the European Union is likely to require the agreement of the other member states of the EU and they may seek to attach extra conditions or negotiate different terms to the terms upon which the UK is currently in the EU. If it can be unilaterally revoked (and the government does so) then it is likely that the Article 50 procedure would have been of no effect and the UK’s membership of the EU would continue on its current terms.
While it is clear that there is currently little or no interest in revoking the Article 50 process within Teresa May's government, those MPs who are unhappy with the proposed deal and find the concept of exiting the EU without a deal unpalatable will await this decision with interest.