For the first time, a second Brexit referendum is a serious possibility

The chaos at Westminster makes a second referendum on Brexit a serious possibility for the first time. If it does happen, the key to successfully designing the referendum process must be to ensure that the legitimacy of the outcome is respected by as many people as possible, in all parts of the country.

First is the referendum question itself. In 2016, as in most other previous referendums in the UK, the choice offered to voters was a simple one: in this case between Remain and Leave. However, as it stands, there are at least three possible ways out of the present political impasse – the Prime Minister’s deal, a no deal Brexit and Remain.

To exclude any of these options from the ballot paper risks undermining the legitimacy of the process. The question is whether all three options could be included on the ballot, to provide both legitimacy and a clear answer.

First-past-the-post would not work

This raises the question of what system should be used to determine the winner.

The simplest approach would be for voters simply to mark their preferred option of the three. The option with most votes would win, as in a general election held on a first-past-the-post basis.

The risk is that the successful option could win with the support of only 40% or so of the electorate – for instance because the pro-Brexit vote would be divided between the two Leave options. This outcome would be contested and could lead to an even more divided nation.

A second option is to use preferential voting

Voters rank the three options in order of preference. The least popular option would then be eliminated and the second preferences reallocated to the other two options. This should ensure that the winning option is either a first or second preference of over 50% of voters. However, this could leave a winning option that scored poorly on first preferences.

A different approach would have two questions

One way of addressing those issues would be to have a two-stage question. Question 1 would be a choice between Leave and Remain, as in 2016. Question 2 would be a choice between the two possible flavours of Brexit: Deal or No Deal.

If Remain won a majority on Question 1, then Brexit would be cancelled.

If Leave won a majority on Question 1, then the results of Question 2 would determine whether the Withdrawal Agreement were ratified (Deal) or whether the UK should walk away on a No Deal basis. All sides in the argument would have had the opportunity to put their option to voters. Another option would be to ask the questions the other way round: the best way to leave and then whether to leave on that basis. But that would have to be done in two separate polls, like the French Presidential election.

But there would still be other difficult issues to resolve

Even a complex two-stage question would run the risk that the four UK nations again vote in different ways.

Parliament would also need to decide if this time it wanted to make the referendum legally binding. The 2016 referendum was ‘advisory’ but a second referendum would have to be definitive – so there are arguments that the result should bind Parliament. That is relatively simple for either the Remain outcome, where the UK would simply revoke Article 50, or No Deal – though the UK may not have much time to prepare to walk away with no transition. 

But it is more problematic in the case of the Prime Minister’s deal: Parliament would have to pass the Withdrawal Agreement but the Political Declaration is, as many people pointed out, miles away from being a clear statement of the UK’s future relationship with the EU, which has to be negotiated after we have left. There would still be scope for many arguments on the shape of that relationship. And Parliament would still want to scrutinise the way in which the Government was choosing to put the Withdrawal Agreement into law, which as we have warned raises important constitutional issues.

The Electoral Commission would, in the normal way, assess the referendum question for intelligibility and bias. It would, in this case, also have to nominate at least three official lead campaign groups: for Remain, Leave/Deal and Leave/No Deal – though there might have to be more, to reflect the choice of second preferences.

A second referendum is only one way out of the present impasse, but with the Prime Minister’s deal facing rejection in the House of Commons, the prospect must be taken seriously. There is a risk that it is seen as an easy way out, and not enough thought is given to how to design it. Should the country be faced with another vote, Parliament and the Electoral Commission must ensure the vote takes place under rules that maximise the chances of the outcome being respected.