The Financial Conduct Authority has already spent more than £250,000 probing so-called debanking after Brexit campaigner Nigel Farage kicked up a storm over Coutts' decision to revoke his account, Financial News can reveal.

Farage found himself at the centre of a banking saga earlier this year after his account at Coutts was closed. Commercial factors had an impact, but staff at the bank had also balked at his outspoken views on issues such as immigration and Brexit.