With hindsight maybe it was silly for me to bleat, ‘As everyone knows, the Johnsons are neither posh nor rich’ on Newsnight just before my older brother published his tax returns showing the impressive sums he’s made in journalism and publishing. I can only imagine how the antlers of rival 12-point stags such as Niall Ferguson and Andrew Roberts must have drooped as they calculated how many copies the full-time Mayor and MP and bestselling ‘popular historian’ must have shifted to earn royalties running into the hundreds of thousands.