There is an old joke among economists that has recently re-entered the discussions: there are at most five people in the world who understand money. Let me borrow this observation. There are at most five people in the UK who understand the EU. I mean, really understand the EU, not just the rose-tinted or resentful caricatures of the EU that that swirls around in the heads of Remainers and Brexiters.

The current polls in the UK are telling us that approximately 60% think that Brexit was a mistake. What this is telling us is that the UK needs to confront the reasons for this. I think it is because the UK lacks an economic model for its post-Brexit existence. But whatever your views, be careful not to draw false converse conclusions. If 60% think that Brexit was a mistake, it does not follow that 60% want to rejoin the EU.

I am hearing the first rumblings of a pro-EU campaign. My advice to Team EU would be: use the time wisely. Do not start where you left off in 2019. In particular, do not think about the deal you can get, or even frame it in terms of a transactional relationship. Instead, think about what you want the EU do, and how you want the UK to contribute. That didn’t happen last time.

Even if the UK were to re-apply, in, say ten years, the EU would surely not offer the same deal to the UK it had when it left. The UK had an opt-out from the euro and the Schengen passport-free travel zone. It also had opt-outs of sorts from the Charter of Fundamental Rights and the entire area of internal security and justice. The UK was not really a full member in the last twenty years of its membership.

By the time the UK will reapply, the EU will have moved on in several policy areas. London is unlikely to regain its status as the eurozone’s financial centre. Frankfurt and Paris have taken some of London’s business. Milan is coming up fast. I recall well that Mario Draghi, in his role as ECB president, was focused on challenging London’s position as the eurozone’s financial centre. The ECB thought it was mad for the world’s second large currency zone to be reliant on a financial centre outside its territory. The ECB can be relied upon to insist that the UK should join the euro if it were to rejoin the EU. Has Team EU even thought about that?

France will almost surely insist that the UK joins the EU’s policies on immigration and home affairs. Why would France want to accept an external EU border on its northern shores when it can outsource that problem to the UK?

We should remember that the EU did not hand the UK its opt-outs on a silver plate. The UK blackmailed the EU into them, by threatening to veto consecutive EU treaty revisions, starting with the one at Maastricht in the early 1990s. But when the UK applies to rejoin, the tables turn. Each of the EU’s current 27 member states will have a veto on UK membership.

One thing that also changed since the UK left is that Germany and France have cemented their powers over regulation. The European Commission has recently proposed the suspension of state aid rules in response to the US inflation reduction act. This will help Germany in particular rig EU economic policy even more in its favour. Germany dominates the regulatory debate in the EU because it speaks for several smaller countries that are part of the wider German economic zone. It is hard to see how the UK could impose itself on this.

There may be options available short of membership. Andrew Duff, a former MEP and clearly one of the five Brits who does understand the EU, has been calling for a reform of European treaties to funnel the EU’s diverse third-country relationship into a single associate membership. I have a lot of sympathies with that proposal, if only because it would open the most realistic pathway I can think of for the UK to re-engage with the EU. But the EU is unfortunately not moving in this direction right now.

The available alternative would be the Norway option. But the UK would once again become subject to EU law, be forced to re-introduce freedom of movement, and not be able to take part in any decisions. I proposed it as a transitory arrangement after Brexit. But it is not suitable as a permanent regime for a large country that seeks to get in.

So if there is ever another referendum, it will not be about regrets, but about whether or the UK should become a full member of the EU, warts and all. I am not sure that Team EU has any chance to win such a referendum, unless its starts to think seriously about the EU itself. The EU would need to change too. It would also be wrong to reduce the goal to the act of rejoining only. The last thing anyone would want is for the UK to rejoin, only to leave again a few years later.

I have come to the conclusion therefore that the best political course of action right now is to make Brexit work. But if you are brave enough, or mad enough, to go for full-Monty EU membership, make sure than the numbers of people in your team with a deep understanding of the matter exceeds five.