The world’s billionaires do not have everything their own way these days. They are still rich and powerful, but they are less feted for exceptional achievement and are under pressure to pay more tax.

Elizabeth Warren, the US presidential candidate, plans a wealth tax to denude the fortunes of those, such as Bill Gates, by tens of billions over decades. “I’m starting to do a little math about what I have left over,” Mr Gates joked last week. Jeremy Corbyn, the UK Labour leader, launched his general election campaign by promising to make billionaires pay a lot more tax.

Billionaires still have some friends. UBS last week sprung to their defence, arguing that its private banking clients merit their wealth. The “smart risk-taking, business focus and determination” of rich entrepreneurs give them the ability “to transform entire industries, to create large numbers of well-paid jobs, and to rally the world to find cures for diseases such as malaria.”