Keep it vague; that seems to have been the strategy adopted in drafting yesterday’s Conservative Party manifesto, at least in so far as the fiscal costs of its various pledges are concerned.

This was plainly a much more credible document in terms of its costings than Labour’s ludicrously unrealistic wishlist, but some of the same criticisms might none the less be levelled at it.

There are lots of promises on extra spending – on health, social care, schools, and so on – and there were also lots of apparent tax “giveaways”, as well as the faintly hollow claim that the Tories remain the party of low taxes; yet there was regrettably little on how it is all going to be paid for.

The answer, though it wasn’t admitted, seemingly lies in another lorry load of borrowing. Ominously, there was also no commitment not to raise taxes on high earners, so we can be pretty sure that in some shape or form, that’s coming down the line at us too.

In any case, somewhat sneakily, the Government has given itself the extra headroom it needs for borrowing more by further finessing its fiscal rules.