Eight months ago, the Financial Conduct Authority singled out a behind-the-scenes, yet essential, part of the financial services industry, when it announced its intention to investigate whether custody banks were, in effect, ripping off their clients.

In the FCA's 2013/2014 Business Plan, it said: "The custody bank business model… is facing strain", which could "lead to harm" to consumers, as custodians are forced to "exploit areas of profitability". Custody banks make money by offering services to pension schemes, hedge funds and other institutional investors, as well as to brokers and banks.