Can Brexit be stopped?

Just as hardline Brexiters are demanding an immediate exit, pro-EU campaigners' calls for a peoples' vote are gaining momentum. Can the UK invoke article 50, and what would a future relationship look like?

“Until negotiations come to an end, there is at least a chance to reopen the door,” declared French president Emmanuel Macron last year. It would be easy to dismiss such optimistic talk as wishful thinking on the part of one of Europe’s most outspoken supporters of the EU project, but a recent court ruling backed up his words.
In a ruling on 10 December 2018, the European Court of Justice stated that the UK could cancel Brexit without the permission of the other 27 EU members. In addition, ECJ judges ruled that the UK has the right to cancel its invocation of Article 50 of the Lisbon Treaty without altering the existing terms of the UK's membership.
The UK government and the European Union opposed the case, which was brought by a group of anti-Brexit politicians who argued the UK should be able to unilaterally halt Brexit.

Chequers Plan

A new Brexit plan that Theresa May and her cabinet agreed in July at a marathon meeting at Chequers would commit the UK to maintain a common rulebook for all goods, including agricultural products with the EU, and would seek continued harmonisation with EU rules to avoid friction at UK-EU borders, including Northern Ireland.
But the plan, which the government hoped could form a blueprint for final-stage negotiations, would end the free movement of people to the UK, as well as the role of the European Court of Justice in UK affairs – both of which EU negotiators would find difficult to accept.
The Chequers plan has also split the ruling Conservatives, leading to high-profile cabinet-level departures and accusations that the concessions to the EU are worse than no trade deal at all.
A more realistic prospect is a second referendum on any Brexit deal that is reached. A YouGov poll in July revealed for the first time that 42% Britons support a referendum on the final terms of a Brexit deal, compared with 40% who do not.
Labour's recent backing for a vote on the final deal, including an option to remain in the EU, keeps the door open to a further referendum, but first they have to get into power.
In early February, the main groups opposed to Brexit agreed to pull together under the banner of the grassroots co-ordinating group, or GCG, to help make a second popular a vote a reality.
Another outcome would be for the government to seek an extension to the Brexit deadline – although, of course, there is no guarantee that a deal could still be reached.

Percentage of Britons who support a referendum on the final terms of a Brexit deal
Percentage of Britons who do not want a further vote on Brexit
Although Theresa May's deal failed to gain support in parliament after MPs voted 432-202 against her deal, she has already survived two votes of no confidence - the first in her leadership of the Conservative Party, and the second in her government.
A general election could still be called, although this would require a two-thirds majority to dissolve parliament and it may prove difficult to persuade the Conservatives to take a chance on losing an election to Labour when they could otherwise remain in power until May 2022.

A second referendum

That leaves the prospect of a second referendum, which appears to be the most realistic way that Brexit could be cancelled. Theresa May has ruled it out under any circumstances, but it could take place if she performed a U-turn. Labour recently changeed tack, aligning with with Tory Europhiles and other opposition parties in calling for a vote on the final deal.
Any referendum would take time to put in place, but Brussels would be inclined to grant an extension in this scenario. The question then would become how a popular vote should be worded. Hardline Brexiters would favour a vote on choosing the negotiated deal or an immediate exit without a deal, arguing that the mandate to leave has already been won. Others are advocating a choice between May’s Chequers deal or staying in the EU.
A third option is a three-way choice between the Chequers deal, no deal or remaining in the EU. Voters would be asked to indicate their first and second choice so that the least-popular option could be eliminated and the vote redistributed.
A second referendum is unlikely to make the issue go away. Brexiters would continue to campaign vigorously, buoyed by resentment that the original vote was undermined.
If a second referendum is agreed and ultimately plays out in favour of remaining in the EU, the question of whether Article 50 is revocable unilaterally, or if it must gain approval from the European Council, gains importance. The overwhelming majority of lawyers believe a unilateral revocation decided in the UK would be legal.
But a second referendum is unlikely to make the issue go away. Brexiters would continue to campaign vigorously, buoyed by resentment that the original vote was undermined. It’s also possible that, under pressure from Eurosceptics, the government may eventually refuse to comply with a piece of EU legislation, triggering a crisis in European integration.
Demonstrators take part in a Brexit protest during the Conservative Party Conference in September 2018

Implications of staying in the EU

On the surface, the UK’s position in the EU would remain unchanged should the decision to leave be reversed. It would continue to have free access to the single market with external agreements made on a common basis. Freedom of movement for EU nationals would also remain in place, and the UK would continue to be subject to all laws and regulations whilst being obliged to contribute to the EU budget.
But the reality is the UK would probably find it difficult to simply pick up where it left off. It would remain in the EU on the same terms that it rejected in 2016, and it’s likely we would see a resurgence of Ukip as an obstructionist force in Brussels. It would also be difficult for a UK government to approve an EU budget that was acceptable to other member states after having placed so much emphasis on waste.
The UK would probably find it difficult to simply pick up where it left off.
The EU has also moved on since the Brexit vote, shortly after which European Council president Donald Tusk declared that the UK’s departure could “threaten western political civilisation”. There are questions over the UK’s input and participation in projects that have been driven since Article 50 was invoked. In particular, the EU has pressed ahead with plans for greater defence co-operation, specifically because the UK was not present to use its veto.
Any short-term changes to the UK’s current trajectory, however, will need to be considered in the long-term context of a major political issue that remains unresolved. 

Brexit insights and analysis from Investec