John Coates at Cambridge’s Judge Business School produced some fascinating analysis last year of testosterone and cortisol among City traders and showed how their abnormally high hormones resulted in increasingly risky, and ultimately stupid, behaviour. The average age of those trading billions of pounds was 26. It’s basic stuff: young males take risks, and most societies have always known that and socialised them through the authority of older men (and marriage). But with the advent of yuppies in the late 1980s anyone over 45 on a trading floor was regarded as a loser; we handed over a pivotal role in our “delicate” economy to those only too happy to take huge risks with it.