A judgment by the EU's highest court today added fire to the Brexit debate by ruling that the UK has the option of revoking its decision to leave the EU - so long as the decision is 'unequivocal and unconditional'. The judgment by the full court in Wightman and Others v Secretary of State for Exiting the European Union had been expected since the advocate general's opinion last week. 

In today’s judgment, the full court states that the option for revocation exists for as long as a withdrawal agreement  between the EU and a member state has not entered into force or, if no such agreement has been concluded, for as long as the notification period is still ongoing. 

The revocation must be decided following a democratic process in accordance with national constitutional requirements, the court states. Such an 'unequivocal and unconditional' decision must be communicated in writing to the European Council.

The decision rejects the arguments of the Council of Ministers and the European Commission that the consent of all other member states would be needed for any revocation of the UK’s withdrawal, as well as the UK government's argument that a court should not be asked to rule on a hypothetical question.  

In its reasoning, the court concludes that the case referred by the Scottish Court of Session raises a genuine issue giving rise to a dispute which it is required to resolve and that the judgment of the Scottish court will have the effect of clarifying the options open to MPs voting on the withdrawal agreement. The question referred by the Court of Session is relevant and not hypothetical, given that it is precisely the point at issue in the pending case brought by Jolyon Maugham QC. 

On the substance of the question, the court rules that article 50 of the Treaty of European Union does not explicitly address the subject of revocation. However article 50 pursues two objectives: first, that of enshrining the sovereign right of a member state to withdraw from the EU and, secondly, that of establishing a procedure to enable such a withdrawal to take place in an orderly fashion. According to the court, the sovereign nature of the right of withdrawal supports the conclusion that the member state concerned has a right to revoke the notification of its intention to withdraw from the EU for as long as a withdrawal agreement has not entered into force or, if no such agreement has been concluded, for as long as the two-year period, and any possible extension, has not expired.

John Halford of London firm Bindmans, who acted for MPs Chris Leslie and Tom Brake as interveners in the case, said: 'This judgment confirms that the UK's sovereign parliament - and no one else - controls the Brexit process and that it has the absolute right to revoke the Article 50 notice if it makes a democratic decision to do so. The government has totally failed in its attempt to prevent parliamentarians from hearing the full range of their options at this decisive moment for our country.'