Who would pay for Rachel Reeves’s increase in employers’ National Insurance contributions? Well yes, in the first instance it is the companies that would have to hand over the cash, but the real burden would be much more widely shared.

To see why, start with the simple question: what does a company do if it finds its labour costs have suddenly gone up? It can do nothing, in which case its profits fall (or even less agreeably, its losses rise) and it pays a bit less in corporation tax.