Pedestrians walk past images of workers of Britain's National Health Service (NHS) fixed to hoardings outside a temporary field hospital, set up in the grounds of St George's Hospital in Tooting, south London. AFP

It shouldn’t surprise you to hear a diehard Remainer say that Brexit was a stupid decision. It has objectively made us poorer and damaged the NHS during a pandemic-fuelled economic crisis. Nobody can call that smart. And a new study this week seems to back that up, by showing that people with higher levels of intelligence were more likely to vote Remain in the Brexit referendum. There’s just one problem, as I see it: I still think it’s wrong to call Leave voters “stupid”.

For starters, the study itself says that the top 10 per cent of the most intelligent people in the UK voted 73 per cent Remain, while the bottom 10 per cent only voted 40 per cent Remain. Sure, that means that intelligence helped. But it still allows for 27 per cent of the most intelligent people in the UK as Leave – and 40 per cent of the least intelligent people as Remain.

Personally, I would call it stupid to treat a 60-40 split as definitive proof of how the whole country is thinking. The report’s lead author explains this trend by reminding us that “low cognitive ability makes people more susceptible to misinformation.”But, in my opinion, it goes much further than that. Some of the Brexit rhetoric was obviously objectively stupid, yet it was believed by people who (I will insist until my dying breath) were not stupid. For example: “The EU needs us more than we need them.” I heard this phrase countless times when speaking to Brexit supporters up and down the country, during the second referendum campaign. That statement really is stupid. Think about it: the 27 EU and three EEA countries would be damaging trade with one of their closest neighbours. We, on the other hand, would be damaging trade with all 30 of our closest neighbours. So who would Brexit damage more? Anyone who actually interrogated the truth of that slogan for more than five seconds would see that it was utterly brainless.

So, if Leave voters weren’t brainless, why did they believe it? I have an answer: it’s because they wanted to. They wanted to believe that the UK was great. Why? Well, for one thing, the Brexit campaigns constantly told people that the UK was more powerful (and generally better) than Europe. They accused “Project fear” Remainers of “talking the country down”. Andrea Leadsom told BBC journalist Emily Maitlis she was being unpatriotic for questioning our success in the negotiations. We can get into how treating opposing views as national betrayal is textbook fascism another time. But if your ideology aligned with that traditional view of “Great Britain”, you probably wouldn’t question someone telling you the EU need us more. This was used to convince people we’d “hold all the cards” in the negotiations, and therefore Brexit would not damage us economically, because we’d negotiate full access to the EU market — without following any of its rules. Yet we’re poorer now — and the numbers prove it. Brexit stupidity isn’t a mental deficiency — it’s an ideology.

That said, it would be wrong to blame the whole thing on wilful ignorance. If I hadn’t studied EU law and worked in EU affairs for years, the idea of not sending £10bn a year abroad (and spending it on the NHS instead) might have convinced me, too. I had to remind myself that sharing rules with the EU makes trade cheaper, saving us a lot more than £10bn. And that has now been proven true, 10 times over. Not all of the 16.1 million Remain voters had law degrees and experience working in the EU institutions. I was lucky to have that experience. I’d worked alongside directly elected members of the European parliament, watching them modify and have the final say on all EU laws. So I was immune to any politician telling me the EU was a dictatorship. But take all that away and put me in a neglected town in the north… Financially strangle me and everyone I love with austerity for six years…

Then tell me that we could save hundreds of millions of pounds a week by voting Leave… and even a genius IQ and a degree in brain surgery wouldn’t stop me from believing it. Sure, the extra intelligence might have helped some people avoid voting for disaster, but it’s woefully naive (and yes, even “stupid”) to call Leave voters “stupid” in turn.

Femi Oluwole, The Independent