Several scenarios could see the vote overturned, involving either a Labour or Tory prime minister. But all are speculative

The British public have voted to leave the EU in an advisory referendum – but there have been voices in business, diplomacy, politics and European polities desperately asking if the issue can be revisited. Is that feasible?



The short answer is yes, just about, but many forces would have to align.

How prepared was the government?

The referendum, for instance, has thrown up big constitutional questions for Britain.

Oliver Letwin, who was appointed by David Cameron, the outgoing prime minister, to oversee the process of withdrawal, is now at the helm of an expanded European secretariat at the Cabinet Office. But it is clear that very little preparatory work has been done. One of the first questions he will face is the future role of the British parliament in Brexit.

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The British government has not yet said how parliament should implement the decision to leave. It is not clear, for instance, if and what laws would have to be passed to put the referendum decision to leave the EU into effect.

Could parliament stop Brexit?

At present, there is not a majority for Britain to leave the EU in either the House of Commons or the House of Lords. Indeed, given a free vote, the unelected Lords would probably reject Brexit by a margin of six to one.

One issue that will arise for the next prime minister – be it Theresa May, Boris Johnson or another – will be what happens when they try to push Brexit through a parliament that can delay the process at every turn. This has been described as a “reverse Maastricht”, a reference to the way in which Eurosceptics caused hell for John Major by blocking passage of the Maastricht treaty into UK law.



Could the referendum be treated as advisory?

The Commons might, for instance, seek to prevent the prime minister from triggering article 50, the clause of the Lisbon treaty that provides the framework of an EU member state’s exit from the union. David Lammy, MP for Tottenham, has had opprobrium heaped upon him for suggesting the referendum should be treated as merely advisory in law, and so ignored. It would seem unlikely that a majority of MPs would be willing to disregard the clear majority of the British people who voted for Brexit.



More plausibly, the Commons might set conditions on the renegotiation, including access to the single market, membership of the European Free Trade Association or the preservation of the union with Scotland. The opportunities to filibuster and delay are innumerable. It is, for instance, disputed whether triggering article 50 requires the authority of parliament. Most legal opinion suggests not, but political necessity may require the endorsement of parliament.



Politics v business

It may also be the case that parliament will wish to be more than simply informed of the government’s negotiating objectives. Those objectives will be at the heart of the Conservative leadership election. The foreign secretary, Philip Hammond, has put the choice well: in essence, there is a trade-off to be negotiated between the degree of access to the EU single market (the concern of UK business) and the degree of free movement of labour (the concern of politics). In the leadership contest both Johnson and May will have to say how much they will make free trade or free movement of people their primary objective in negotiations.

The candidates would also have to explain whether they believed the settlement at some point, in outline or detail, should be subject to some further democratic test, possibly in a spring 2017 election.



Scenarios for a second referendum

There is also pressure to hold a second referendum. Few UK politicians – fearful of challenging the verdict of an already angry electorate – will articulate such an argument in public. But Jeremy Hunt, the health secretary, has boldly made the case for a second referendum or another general election on the negotiated terms of exit. Robin Butler, the former head of the civil service, has suggested the same.

Hammond, the foreign secretary, has said the new prime minister will need to think about the democratic legitimacy of the terms of Brexit. At one point even Johnson, and Dominic Cummings, the director of the Vote Leave campaign, made the case for a second referendum on the terms of a Brexit.

Despite the Fixed-Term Parliament Act requiring a parliament to last five years, it is possible for an early election to be called if enough politicians support this.



For the sake of simplicity, three scenarios could then follow. In the first, Johnson wins the election, negotiates the terms of the UK’s departure, puts them to a referendum and they are endorsed. Some form of access to the single market and some deal on free movement – the two central issues – are agreed. It is a bespoke British deal. Britain remains outside the EU but only just.



The Labour option

The second scenario is that Labour, under a new leader, offers itself as a pro-European party, but promises to seek a new deal on free movement of workers within the EU.



A change on free movement is the chief route back to its evaporating working-class vote, as Yvette Cooper, the former shadow home secretary, pointed out in a speech on Tuesday. For this to happen, the EU would need to offer an “emergency brake”, something Angela Merkel, the German chancellor, has steadfastly refused in her talks with Cameron. But many in the Foreign Office hope she would relent, or would be forced to do by the French and Italians.

In its manifesto for a 2017 election, Labour said it would give the British people a second referendum on the precise terms of the negotiations.

Labour would seek to capitalise on a potential new deal on immigration with the EU, the buyers’ remorse of leave voters regretting their decision, evidence of the real world economic chaos created by the prospect of Brexit, and a Labour leader with appeal on the doorstep.

If an election result then returned a second Commons with a pro-EU majority, this could prevent the UK leaving the union. A mandate for a second referendum on the terms of Brexit, or staying in, would have been provided.

Scottish consent

The third, simpler scenario involves the Scottish Nationalists.

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The first minister, Nicola Sturgeon, has already said she would tell her MSPs to refuse “legislative consent” if and when the Scottish parliament was required to ratify the UK’s withdrawal from the EU.

Speaking to the BBC, she said: “If the Scottish parliament was judging this on the basis of what’s right for Scotland then the option of saying ‘look, we’re not to vote for something that’s against Scotland’s interest’, of course that’s got to be on the table.”

The constitutional implications of Scottish politicians withholding consent are only now being explored.



All these scenarios, however, are inherently speculative – and require an accumulator bet coming good – but if you think it is not being discussed in Whitehall and Westminster, you are mistaken.