How would a new EU referendum work?

Remain supporters gather outside Parliament the day after the Brexit vote in June (AP)

Our chief political commentator analyses the practicalities of organising another referendum on the final terms of Britain’s exit from the EU

1. Can Article 50 be reversed?

   The text of Article 50 says nothing about a country changing its mind before the two-year period is up. It says the deadline could be extended if all EU countries agree, and it says that, after it has left, a state can apply to rejoin in the usual way.

   The opinion of Lord Kerr, the British diplomat who drafted Article 50, is that it would be legally possible for the UK to withdraw its notification under the clause. Ultimately, the legal position would have to be decided by the European Court of Justice. In practice it would be a political decision: it would only go to court if there was a disagreement.

   So, if the British Government sought to cancel Brexit, possibly after holding another referendum, it is almost certain that the other nations of the EU would agree, and many of their leaders have already said so.

2. Would the EU demand concessions in return for cancelling Brexit?

   It has been suggested that the EU might insist the UK adopt the euro, join the Schengen passport-free area or give up its rebate, but those would make more sense if we were applying to rejoin after leaving. If we decided not to leave and wanted to keep things as they are, the other EU countries are unlikely to risk driving us away again by imposing conditions.

   On the other hand, it has already been decided that the medicines and banking regulators are leaving London. We won’t get them back.

3. When would a referendum need to be held?

   Working backwards from the deadline set by Article 50, a referendum to cancel Brexit would have to be held in good time before 29 March 2019. The other EU countries would have to agree, so it would be only diplomatic to give them time to consider our decision – if the referendum so decided – to withdraw our notice of intention to leave.

   The EU usually takes its time about such things. If we were to respect its normal timetable, this is a decision that should be taken at the EU Council in a year’s time, 13-14 December 2018 (the next Council on 21-22 March 2019 is just a week from Brexit day). To give countries time to consider, the referendum would have to be held in November next year.

   In practice, and if the EU27 were keen to keep us in, they would agree to an emergency council in January or February, which suggests that January 2019 would be the latest possible date for a referendum.

4. How long did the last one take?

   The EU referendum in June 2016 was called by David Cameron in February, four months earlier. But the law providing for it took seven months to get through Parliament the previous year. This timetable could be shortened dramatically, especially if the pro-EU majority in the House of Lords supports it. A new referendum act – the wording could be based on the 2015 act – could be rushed through in two weeks if there is a clear majority for it in both Houses of Parliament.

   The Electoral Commission recommended, after the last referendum, that “referendum legislation should be clear at least six months before it is required to be implemented or complied with”. Too bad. It would have to be told that it had two months last time, and that is all it is going to get.

5. So when would the deadline be to decide?

   In that case, assuming a 10-week campaign period like last time, the decision to prepare for a referendum would need to be taken five months before the date of the vote. That means August next year for the latest possible referendum in January 2019.

   Assuming the timetable could be compressed further, it would be possible to decide in September or October 2018 to hold a referendum.

6. What would be the question on the ballot paper?

   The choice would have to be between leaving the EU on the agreed terms or staying. This could be awkward, as the terms might not be agreed by the time the decision to hold a referendum has to be taken. The deadline set by Michel Barnier, the EU negotiator, is October 2018. The outline of a deal might be clear by then and the terms of the deal would have to be sealed by the time of the vote, because they have to be approved by other member states.

   The wording in 2016 was simple: “Should the UK remain a member of the EU or leave the EU?” It could be argued that simply to repeat it would bias the vote towards “leave” because it would imply that the answer people gave last time was the wrong one. On the other hand it might unbalance the question if the leave option included “... on the terms negotiated by HM Government?”

   It would be harder still to draft a question if no agreement had been reached or seemed likely to be reached: “... in the absence of agreement between HM Government and the rest of the EU?”

7. What about the option of further talks?

   Some people might argue for a multiple-choice referendum, with further negotiations as a third option. But, although the UK can ask for an extension of the Article 50 deadline, it is up to the other 27 countries to agree. They would probably agree to cancel Brexit, but we cannot assume that they would agree to an extension. It is not really a suitable question for a referendum.

8. What would the outcome be if a referendum took place today?

   According to today’s opinion polls, the result would be close. A Survation poll carried out at the start of the month found 48 per cent would vote to leave and 52 per cent to remain, if they were asked the same question as last time. This is the reverse of the result in 2016, but the average of the opinion polls then suggested “remain” had a small lead.

   Furthermore, this ignores the dynamics of the campaign. It would be possible to hold another referendum only if public opinion had moved significantly and the Labour Party had changed its position. But calling a referendum might have the effect of energising those who feel the result of a democratic vote is being overturned, thus raising motivation and turnout among Brexit supporters.

9. How much do referendums cost?

   The last referendum cost the taxpayer £137m, according to the Electoral Commission. This amounts to £2.95 per registered elector.

10. What about a general election instead?

    Many Remainers, including Peter Mandelson, say that the final deal ought to be put to the British people “either in a new referendum or in a general election”. In principle, the specific mandate of the 2016 referendum should need a further referendum to reverse it. It could be argued that an election won by a party or parties (Labour, the Liberal Democrats and Scottish and Welsh nationalists) on an explicit anti-Brexit platform would have the same effect, but the problem is one of timing.

    Leaving aside the problem of converting the Labour leadership to that policy, unless Brexit day is delayed, the prospect of an election before then is remote. The Conservatives and DUP have a majority in the Commons and neither party wants an early election.