Should an election or a referendum come first? While it is obvious that an election cannot resolve Brexit, the concern about waiting for a referendum is that it would take too long; who would govern in the interim and with what mandate?

However, that concern is based on the false premise that a referendum would take a minimum of 22 weeks to organise. This assumption is based largely on the application of existing legislation, reviewed in a report in October 2018 by The Constitution Unit and The UK in a Changing Europe organisations.

However, what seems to have been forgotten is that in the 1975 referendum, on whether Britain should stay in European Economic Community, it took only nine weeks from the introduction of legislation to the holding of the vote and three of those were taken up with waiting for royal assent. In effect, the referendum took six weeks. It is fair to say that there was a preceding white paper, but it shows that a speedy referendum is possible.

There would be huge advantages to such a course – it would quickly produce much-needed certainty and reduce the time available for further social division. Just as in 1975, people have debated the issues ad nauseam – what is needed now is a chance to vote. It would also cut the time available for massive expenditure. This is important because the rules in relation to campaign spending limits have recently been rendered pointless by a court of appeal decision, which held that campaigns may donate goods and services to other campaigns without them counting as their own “referendum expenses”. In effect, therefore, campaigns are no longer subject to spending limits under the Political Parties, Elections and Referendums Act 2000.

Most importantly, pursuing such a course could crack what have seemed like insuperable obstacles. The first is the vexed question of who would run a caretaker government. While Jeremy Corbyn has been criticised for not standing aside to allow a more neutral figure to take charge, his position is hardly surprising. As leader of the opposition, Corbyn would normally take on the role of leader of an interim government following a vote of no confidence. In ceding it to a government of national unity, he would not only relegate himself to the backbenches but give up his place as leader of the opposition to Boris Johnson. Labour would also lose “Short money”, funds paid to the opposition.

But it is equally unsurprising that those who oppose Corbyn refuse to support him being installed in No 10, fearing that it could potentially be for as long as six months, during which time no one will know what he might do or what electoral advantage he might gain. A six-week period might be short enough to allay those concerns. Equally, it may be short enough for Corbyn to accept an alternative figurehead, after which an election and normal politics would resume.

Facebook Twitter Pinterest ‘As leader of the opposition, Corbyn would normally take on the role of leader of an interim government following a vote of no confidence.’ Photograph: Stefan Rousseau/PA

The second obstacle is the length of any extension that the EU is willing to grant. The longer there is delay and uncertainty, the more problematic it will be for business and the EU itself. Organising a referendum quickly would bring closure quickly, which would benefit everyone.

The third obstacle is whether a referendum or election should come first. An election can be arranged quickly and in that sense is superficially attractive as a first step. But it cannot provide a clear mandate for any particular course on Brexit. A government based on 37% of the electorate could not claim a mandate either for “no deal” or for “revoke”. As for a coalition, or confidence and supply, government, it is difficult to see what mandate it would have. Only a referendum can produce a clear outcome and allow closure. If it could be arranged as quickly as an election, even the superficial attraction of holding an election first falls away.

A referendum could only provide closure, however, if its result were legitimate, certain and could immediately be implemented. Therefore, it would be most sensible for it to follow the 1979 Scottish post-legislative referendum, in which the relevant legislation was to come into effect on an affirmative vote or, if rejected, would fall away. The way to do that would be for the 2018 withdrawal agreement (which Johnson voted for) and its implementing legislation – the withdrawal and implementation bill – to be debated and adopted by parliament, subject to confirmation by referendum, following which the agreement would be ratified and the bill would come into effect.

If rejected, the prime minister would be required to revoke the article 50 notification to the EU. The consequence would be that within days of the referendum result the position of the United Kingdom would be final and clear in national and international law.

People may argue that not allowing no deal on the ballot would remove legitimacy in the eyes of many. But no deal would not provide closure, it being uncertain in its meaning. Moreover, parliament has overwhelmingly voted against it on the basis that it would be catastrophic in its consequences for the future of this country, including real risk to lives and livelihoods. It is difficult to see how any liberal democracy, that is, a rule-of-law-based system that safeguards fundamental rights and freedoms, could put that to the people as a legitimate choice.

• Jessica Simor is a barrister at Matrix Chambers