An estimated 2.4 million customers quit the UK’s five biggest banks in 2012 as people “voted with their feet” in response to a string of scandals, according to latest figures.

The Move Your Money UK campaign and website, which issued the figures, said they showed a “mass movement” away from the big banking groups: Lloyds, Royal Bank of Scotland/NatWest, Barclays, HSBC and Santander.

Laura Willoughby, Move Your Money chief executive, said: “The constant slew of scandals last year has opened the floodgates, and people are beginning to realise they don’t have to put up with the arrogance of the big banks.”

The Libor rate-fixing affair, bankers’ bonuses and a wave of scandals and regulatory clampdowns involving the mis-selling of products such as payment protection insurance and interest rate swaps have all fuelled anti-bank sentiment, and created an appetite for challenger brands within the sector. The campaign group said local, ethical and mutual financial service providers were among those that had increased their customer base significantly.

Willoughby, speaking at a debate at St Paul’s Cathedral in the City of London on the future of banking, said people were switching “because they are angry about the lack of reform in Britain’s broken banking system, and have decided to take matters into their own hands”.

She said the campaign group’s data, drawn from industry studies, supported anecdotal evidence and growth figures from alternative providers.

The acceleration in people moving away from the big banks could be fuelled by a forthcoming change in the rules governing switching. From September, the whole process of moving a current account must be completed in seven working days.