ON Monday it will be exactly three years since the last general election.

Previously solid Labour seats in the north of England went to the Tories for the first time that anyone could remember, and it was put down to two factors: distrust of Jeremy Corbyn and Boris Johnson’s promise to “get Brexit done”.

Like most people, including most politicians, I had planned to ignore Brexit from now on. I thought it was a terrible idea, and knew I would be in a position to say: “I told you so.”

But we are where we are and we’ll have to get on with it.

However it’s becoming impossible to ignore. And if the last election really was “the Brexit election”, then the outcome now could be radically different.

Support for Brexit is at an all-time low.

A YouGov survey finds that only 32 per cent of Britons believe it was right to leave the EU and 56 per cent think it was wrong.

Support is even dropping among Brexiteers. One in five of those who voted leave now believe it was a mistake.

It is worth remembering that support for Brexit was never as high as it seemed. It wasn’t 52 per cent of the entire population who voted for it in 2016, just 52 per cent of people who turned out to vote in the first place.

Many remainers – such as David Cameron and George Osborne – were confident their side would win and didn’t bother to turn out.

The fact is that Brexit is possibly the single biggest mistake of the post-war era and people are beginning to realise it. For the evidence is piling up.

According to the Organisation for Economic Co-operation and Development, Britain’s economy will be the weakest performer among the world’s big economies next year, with the one exception of Russia.

Last week Andrew Bailey, the governor of the Bank of England, confirmed that Brexit is the main reason why the British economy is contracting while the eurozone and the US are growing.

The Bank’s former policymaker, Michael Saunders, added that Brexit “has permanently damaged the UK economy”.

Now there’s even more evidence. The first major free trade agreement signed by Britain after Brexit has turned out to be a failure.

When Liz Truss was trade secretary back in October 2020, she signed a “historic deal” with Japan, a “landmark moment for Britain” which was going to boost trade by billions of pounds and help compensate for losses from leaving the EU single market.

However, figures from the Department for International Trade show exports to Japan have fallen between now and then.

These post-Brexit trade deals aren’t looking promising. The one with Australia was criticised by former environment secretary George Eustice, who said it was “not actually a very good deal for the UK”.

We didn’t need economists or politicians to tell us this would happen. You can’t erect a barrier between yourselves and your closest neighbour – with whom you did 40 per cent of your trade – and not notice any harm.

Of course those who are determined to support Brexit might look for other, non-economic benefits, such as a drop in immigration, if that was necessarily a good thing.

Immigration has actually increased since Brexit.

Some people went on believing that the world was flat against all the evidence, but over time fewer and fewer held onto that belief. Brexiteer numbers are dwindling in the same way.

Ignoring Brexit was never going to be possible. It has been dogging us for the last six years and it isn’t going to go away. It will hang there forever until eventually it’s reversed.

No politician is going to dare suggest rejoining at the moment for fear of being slaughtered by the national tabloid newspapers who branded remainers “traitors” and judges “enemies of the people”, and poisoned the minds of their readers against the EU in the first place.

But as everyone noticed, the referendum opened up divisions across the UK – between city and country, between graduates and non-graduates, between Scotland and England, and between the young and the over-65s.

And the over-65s are running out of time.

I assumed that in a generation, when today’s young remainers become our political rulers, they will lead us back into the EU – provided the EU will still have us. An independent Scotland will probably have already rejoined by then.

But we may not need to wait a generation, if this YouGov is anything to go by.

It hasn’t taken a generation to prove to the Brexiteers that they got it badly wrong.