The economists Emmanuel Saez and Thomas Piketty studied the incomes of the top 0.1% of earners in America, Britain and France in 1913-2008.

But work by two academics, Thomas Piketty and Emmanuel Saez, shows that inequality has been just as marked in pre-tax as in post-tax incomes.

But a commenter quickly notes that Mr Winship made a mistake here: he used Messrs Saez and Piketty's figures for income not including capital gains.