WHAT would happen after a vote for Brexit on June 23rd? The short answer is that nobody can be sure, because there is no precedent. Greenland voted to leave the club in 1982, but it is part of Denmark, has only 50,000 people and fishing was the only big issue. Even so it took three years to establish a new relationship.

If there is a Brexit vote, David Cameron has promised that Britain would “straightaway” invoke Article 50 of the Lisbon treaty, which sets a two-year timetable to agree the terms of departure. The other 27 EU countries would decide (by majority vote, without British participation) what offer to make. There would almost certainly be parallel negotiations on a new trade deal, which would need unanimous approval by all 27 countries and their national parliaments. The European Parliament would have to endorse both deals. If no agreement is struck within two years, the timetable can be extended, but only by unanimity—if that is not done, Britain would have to leave with no deal at all.

If this seems designed to give more bargaining power to the EU than to a post-Brexit Britain, that was part of the intention of article 50. Worse, the EU in its current fragile state would not wish to be generous, for fear that others might follow. The argument that the big British trade deficit makes the EU more dependent on Britain than the other way round might carry some weight with big German or Dutch exporters, but not with countries like Romania or Slovenia that export little to Britain.

Given all this, some Brexiteers have been searching for an alternative to the immediate use of article 50. One idea is to put it off and negotiate a new relationship informally. Most diplomats reckon the EU would simply refuse to negotiate until Britain invokes article 50. Another proposal is not to use the article at all but instead repeal the 1972 European Communities Act that gives effect to EU laws, or pass a new act taking Britain out of the jurisdiction of the European Court of Justice. But unilateral action would put Britain in breach of European and international law. As Alan Renwick at the UCL constitution unit adds, it would not be conducive to a friendly climate for further negotiations.

Greenland did it The fact is that article 50 is the only legal way to leave the EU. It might not have to be invoked instantly, but Britons who had just voted to leave would expect it to be done quickly. And, once invoked, the two-year clock starts ticking. So some Brexiteers have raised another possibility: that a vote for Brexit could produce a new offer of better membership terms, including the ending of free movement of people, that could lead to a second referendum. Many point to Denmark and Ireland, which each had to vote twice before ratifying EU treaties.