The UK can halt Brexit by unilaterally revoking the Article 50 notification, a top EU law officer has said.
Campos Sanchez-Bordona, European Court of Justice (ECJ) advocate general, told the EU’s top court it should allow the UK to withdraw its notice of intent to leave the bloc.
Although his opinion is not binding, the ECJ tends to follow the advocate general’s stance in its final rulings.
The news has been seized on by those opposed to Brexit and campaigning for a second EU referendum.
Meanwhile, those supporting the prime minister’s Brexit deal have said it adds urgency to the need for Leave-supporting MPs to back Theresa May’s agreement in a House of Commons vote next week.
The pound rose a cent to $1.28 on the advocate general’s opinion on Tuesday morning.
Mr Sanchez-Bordona gave his opinion on a case brought to the ECJ by a cross-party group of Scottish politicians, which was heard by judges at the Luxembourg court last week.
He proposed on Tuesday the ECJ “should, in its future judgement, declare that Article 50 TEU [Treaty of the European Union] allows the unilateral revocation of the notification of the intention to withdraw from the EU, until such time as the withdrawal agreement is formally concluded”.
This must be done in line with a member state’s “constitutional requirements” and not as part of “an abusive practice”.
In January last year, the UK’s Supreme Court ruled parliament would have to approve the triggering of Article 50 and said it could not be done by ministers alone.
Mr Sanchez-Bordona added the dispute is “genuine” and the question of whether Article 50 can be revoked “is not merely academic, nor premature or superfluous, but has obvious practical importance and is essential in order to resolve the dispute”.
He rejected suggestions the UK could only revoke its Article 50 notification with the unanimous approval of the 27 other EU member states.
The case was brought by a group including SNP MP Joanna Cherry, SNP MEP Alyn Smith, Labour MEPs David Martin and Catherine Stihler, Green MSPs Andy Wightman and Ross Greer, and barrister Jolyon Maugham.
Liberal Democrat Brexit spokesperson Tom Brake and Labour MP Chris Leslie were listed as additional parties in court documents.
Lord Kerr, a former diplomat who helped write Article 50, now backs the People’s Vote campaign for a second EU referendum.
Responding to the advocate general’s opinion, he said: “This is no surprise and, if the court agrees, will confirm that it is still up to us to decide whether we want to keep the existing deal we’ve got in the EU rather than leave on the government’s terms.
“The choice facing us is not simply between the government’s deal and no deal. We can choose to change course.
“There is still time and, until the UK has left the EU, the Article 50 letter can be withdrawn.”
Ian Blackford MP, the SNP’s Westminster leader, said: “This is what we believed is the case. Scotland voted to Remain, leaving would hit jobs and prosperity. It is not a price worth paying.
“We can now press the pause button whilst proclaiming the case Scotland wants to remain in the EU. We should not be dragged out against our will.”
Mr Maugham said: “This puts the decision about our future back into the hands of our own elected representatives – where it belongs.
“On this critical issue I’m sure MPs will now search their consciences and act in the best interests of the country.”
Solicitor General Robert Buckland used Mr Sanchez-Bordona’s opinion to press the case for Tory MPs to drop their opposition to the prime minister’s Brexit deal.
He told Sky News: “Quite clearly the issue of no Brexit does arise and that’s why it’s vitally important this place, parliament, makes a decision and gets on with the job and actually votes for the deal so we can avoid the uncertainty that will inevitably follow if this place doesn’t make up its mind.”
He added: “If parliament took matters into its own hands and sought to revoke Article 50, that’s a direct threat to the vote that was cast to millions of people and to Brexit itself.”
The UK government had tried to prevent the case, which started in the Scottish courts, from reaching the ECJ.
Lawyers representing the government argued it was inadmissible because it involved a hypothetical question, with ministers having repeatedly stated they had no intention of withdrawing the Article 50 notification.
At the four-hour hearing last week, Lord Keen, acting for the UK government, argued the unilateral revocation of Article 50 would give “political ammunition” to Remainers.
He said: “In Greek myth, Pandora was given a large box on her wedding which she was told not to open.
“We respectfully plead the court should not open this box.”
The wording of Article 50 of the Lisbon Treaty, the mechanism for a member state to quit the EU, makes no mention of whether a notification of intent to leave can be revoked.
However, it does allow for the Article 50 period – during which a withdrawal agreement is negotiated – to be extended beyond two years if both the departing member state and all other countries agree.
Mrs May has said she will not try and extend Article 50, while the EU has shown no appetite for an extension simply for further exit negotiations.
MPs will begin a five-day debate on Mrs May’s Brexit deal later on Tuesday, with a vote due to be held on 11 December.
It is estimated she will be at least 90 votes short of winning the House of Commons’ support for her agreement.