The reluctance among the biggest banks to disclose the ethnic breakdown of their staff has angered campaigners, who accuse the banks of undermining efforts to diversify the City's workforce.

Of the 10 largest banks that operate in the City, Barclays was the only one willing to provide data to Financial News detailing the ethnic mix of its staff. Deutsche Bank, Credit Suisse, Morgan Stanley, HSBC and UBS were unable to provide the data, despite all of them promoting their diversity policies online.