The report by Cass Business School for New City Agenda noted that poor culture has costed British retail banks and building societies in terms of fines and compensations to customers and at least £27bn was due to the mis-selling of personal protection insurance (PPI).

According to the report, poor customer service was offered due to poor banking culture.

Between 2008 and the first half of 2014 banks have received 20.8 million complaints, and 25 million between 2006 and the first half of 2014 .

In 2013/14, the number of complaints to the Financial Ombudsman is said to have increased over fivefold from 75,000 in 2008/09 to 400,000.

Over two decades, staff in some branches received cash bonuses, ipods, or tickets to Wimbledon for hitting ambitious sales targets due to which an aggressive sales culture took hold in retail banking.

Cass Business School report author Professor Andre Spicer said: "A few years ago, it became clear Britain’s banks were broken. A toxic sales culture had taken hold and public trust was at an all-time low. We wanted to find out how they were being repaired.

"We found that some progress has been made. Regulation has improved, and big banks have all implemented new programmes to improve their cultures. Smaller banks and challenger banks are beginning to offer the customer real choice, and often have healthier cultures."

In order to bring in change most banks have implemented top-down culture change initiatives, by altering performance frameworks.