Do the Labour Party’s numbers add up? If I had a penny for every time I’ve been asked that in the past 24 hours, that alone might have given me enough cash to be among the 5 per cent of people they say will be asked for more income tax.

The short answer is, as of yet, I don’t know. The longer answer is to ask whether the question even makes sense in the context of a set of proposals that would represent such a big change from where we are now.

What do we know? Well Labour has said it wants to spend an extra £25 billion a year on investment and infrastructure projects. It has also said it is happy to borrow to