In September 2008 wealthy customers at a UK private bank were offered the alternative investment opportunity of the year: a chance to put money into a portfolio of five of Europe’s most-prominent activist hedge funds, including The Children’s Investment Fund, Atticus, Toscafund, Hermitage and Centaurus.

The bank reasoned that activist strategies, which typically involve taking stakes in companies and lobbying their boards for change, were set to outperform. So much so that it offered its customers a significant margin: for every pound they invested, the bank would lend them another four.