2:30
12 July 2013
24 December 2013 Last updated at 10:12 GMT
Santander UK's Chief Executive Ana Botin has been talking about rebuilding reputation after another challenging year for Britain's banks.
Banks paid a total of £148bn in fines this year, calculates the London School of Economics, following insurance mis-selling and rate-fixing scandals.
"Trust is the essence of banking," Ms Botin told BBC Breakfast's Steph McGovern, adding that she wanted all her customers to be happy: "You need to aspire to be the best... My goal is to reach four million [loyal customers] by 2015."