Europe’s highest court will issue decision ‘quickly’ on whether the UK can reverse Brexit

Judges at the European Court of Justice (ECJ) are set to decide "quickly" whether or not the UK can reverse Article 50, the mechanism by which it withdrew from the bloc, without permission from other member states.

Britain is set to leave the EU on 29 March next year under the terms of Article 50, which MPs triggered in a vote last year.

But a case to reverse that vote has been brought by a group of Scottish politicians who argue that Article 50 can be revoked and that June's 2016 referendum was not legally binding.

The ECJ is hearing the case today and judges said they would deliver a decision “quickly”, according to Reuters, but did not give a specific date.

“These petitioners need to know the options for revocation which are open to withdrawing member states now, to allow them – properly and in a fully informed way – to carry out their duties as democratically elected representatives,” said Aidan O’Neill, a lawyer for the politicians, according to Reuters.

Under Article 50, any country that wishes to withdraw from the EU has until two years to agree an exit deal, a deadline that can only be extended with the permission of all other 27 EU member states.

If the ECJ rules in the SNP politicians' favour it will give hope to those advocating a second referendum as it would show that no Brexit is an alternative to both the deal struck by May and no deal.

Lawyers for the government have argued that any ECJ ruling would be irrelevant as a second referendum is against government policy.

Meanwhile, lawyers for the EU warned that allowing the UK to reverse its departure without the agreement of other member states could open the door for other countries to abuse the exit process.

Hubert Legal, speaking for the EU's executive commission, said countries could give notice of their decision to leave before seeking better terms in order to remain in the bloc, Reuters reported.

The legal challenge comes as May prepares to sell her Brexit deal to the House of Commons, which is set to pass or reject it in a vote on 11 December. She is facing opposition from MPs across all parties.

This morning, former defence secretary Michael Fallon said May's Brexit deal was "doomed" and must be renegotiated – an option that has been ruled out by EU negotiators who have said it is the "only deal possible".