This is such a bad idea that the obvious explanation is that one of Keir Starmer’s advisers had a bet with a colleague about the most absurd story that they could get into the press.

The real reason, though, is probably that people in Downing Street and the Treasury are desperate. They know that the Budget is going to be bad – and possibly career-ending for the chancellor. Maybe even the prime minister, too. So they are floating all kinds of unlikely ideas in the hope that one of them might work in making next month’s medicine more palatable to the voters.

Starmer and Rachel Reeves are “expected to argue” that Nigel Farage and Brexit are to blame for the tax rises in the Budget, according to The Times. The reasoning goes that a large part of the shortfall in the public finances comes from a downgrade in the forecast productivity of the British economy, and that this is because the negative effects of leaving the EU single market are greater than previously thought.

Therefore, as The Times puts it, Farage is responsible for putting up your taxes “as the man who delivered Brexit with ‘easy sloganeering’ then walked away from the aftermath”.

That is not going to work. It may be a form of wish-fulfilment for some passionate Remainers who want Farage to pay for what they regard as the disaster of Brexit, but even they, if they are honest about it, would have to admit that the logic is faulty.

What Labour has to explain is why the Office for Budget Responsibility (OBR) forecast has become worse since this time last year. That cannot be, because we left the EU five years ago. The timing of the downgrade in the OBR’s forecast of productivity is unfortunate, but a change in the estimate of the effects of Brexit is not something that was caused by Brexit – and still less something that was Farage’s fault.

Of course, this is not logic, it is politics. You can see how people might think it would work as a vibe rather than an argument. Brexit has made us poorer than we would otherwise be, so anything that makes us poorer, such as tax rises, can be associated with it. In addition, public opinion has turned against Brexit, in that a majority now says we were “wrong to leave”, so would it not help Labour to remind voters that Farage was its great cheerleader?

I think the short answer is: no – and I will explain why in a moment. But it is worth noting another important feature of this argument, which is that it runs counter to the dominant strategy of the government, as set by Morgan McSweeney, Starmer’s chief of staff.

McSweeney sees the current political battlefield as a fight between Labour and Reform. He does not believe that moving to the “left”, which includes these days moving to a more pro-EU position, is the way to keep voters who are tempted to abandon Labour for the Lib Dems, Greens and the Corbyn-Sultana party.

McSweeney’s view is that Labour should focus on voters who are tempted to defect to Reform, and that presenting the next election as a choice of prime minister between Starmer and Farage will also keep enough of the left onside.

I think he is right, because most marginal seats, on current levels of support, are Labour-Reform contests. They are where the next election will be decided. To tell the voters in those seats that anyone who voted Leave is to blame for the absence of milk, honey and the sunlit uplands is unwise.

But it is also wrong. Farage did not lead the Leave campaign. He did not negotiate and implement Brexit. Specifically, he did not design a post-Brexit migration system that allowed a quadrupling of net immigration.

Many Leave voters were prepared to pay an economic price for national sovereignty, although they thought the better-off would pay it, because they thought less immigration would benefit the lower paid. But what they wanted was less immigration. They didn’t get it.

They are like those starry-eyed Marxists who say, “real socialism has never been tried”, except that they are right: Brexit could have been done differently, and it is not Farage’s fault that it resulted in more immigration instead of less.

It is certainly not Farage’s fault that taxes are going to go up in this Budget. It may be that Brexit has made us poorer than we would otherwise be, but Labour’s promise at the last election was to “make Brexit work”.

Starmer and Reeves are going to have to find a better scapegoat.