When the investment industry is in general agreement about something it often pays to be sceptical. As the great Warren Buffett says, it is usually good to be a seller when everyone else is a buyer.

And so it has proved with the claim that stocks with high ratings on environmental, social and governance (ESG) factors outperformed during the stock market downturn triggered by the coronavirus outbreak. Dozens of firms from BlackRock down trumpeted the performance, which they said showed that following ESG principles helped investors select stocks that would be resilient in a crisis.