Show me a man of money, and I will show you a genius.” So intoned Malcolm Eden, of 1980s UK guitar band McCarthy, on the track “Governing Takes Brains”. I know, as I was a broke young man listening to him in an empty student bar. I wasn’t sure whether to be slightly amused, faintly encouraged or frankly outraged that such myths of a hierarchical class structure could be perpetuated in a post-capitalist society. It was a long time ago.

I was reminded of the line last month, when I read about a present-day student who appeared to have proved the hypothesis. Jonathan Wai, a research scientist at Duke University in the US, published an article last year arguing that the wealthiest individuals have the greatest cognitive ability. Or, as he put it, “the top 1 per cent in wealth highly overlaps with the top 1 per cent in brains”.

By extrapolating IQs from likely academic test scores, Wai deduced that about 45 per cent of billionaires are in the top 1 per cent of cognitive ability, making them statistically more intelligent than Fortune 500 chief executives (which may seem surprising) and US senators (which may seem less so).