For many people, news of Barclays' involvement in attempts to fix crucial inter-bank lending rates was the last straw, after a spate of revelations from across the sector about sky-high executive bonuses, irresponsible lending, poor customer service and IT mismanagement.
In July, according to the Building Societies Association, societies and other mutuals – which are owned by members rather than shareholders – took in more than £1 billion of savings cash and provided more than a quarter of all new mortgages.
Meanwhile, independent pressure group Move Your Money estimates that, between January and July, 500,000 people switched their current account to a mutual or co-operative, and 50,000 started saving with a customer-owned credit union, boosting their UK membership to more than one million.
Move Your Money wants to make people more aware of the alternatives to the big banks.
Apart from building societies and credit unions, these include ethical banks, such as the Co-operative, Smile (both part of the same member-owned group), Triodos and Charity Bank – which are all committed to socially responsible lending – and co-operatives like Zopa that link potential borrowers and lenders.
Many of the larger building societies, ethical banks and credit unions offer current and savings accounts, mortgages and personal loans. Others, such as the smaller unions and lending co-operatives, concentrate on providing straightforward, competitive savings and loans.
Move Your Money founder Louis Brooke explained: "It kicked off on the back of a pub chat with a small group of friends. Scandal after scandal has shown how the banking sector has put short-term profit ahead of customers.
"We wanted to let ordinary people know that there is another way of organising your finances. A similar campaign in America encouraged about 10 million people to move their money."
Mr Brooke insists that shunning the big providers can make financial as well as moral sense. He said: "There doesn't have to be a conflict between getting the best deal and building a better financial system."
Data from product comparison websites bears this out, with mutuals featuring consistently in best-buy tables for savings, mortgages and personal loans.
In the independent Moneyfacts Awards 2012, which recognise product excellence, building societies and ethical banks won or were commended in 14 out of 26 categories. Yorkshire Building Society took three awards, including best short- and longer-term fixed-rate mortgage provider, while Nationwide was best internet account provider.
Dunfermline Building Society, which is part of Nationwide Group, received a commendation for its notice savings accounts. Dunfermline's branch-based Platinum Monthly Saver pays 5% interest.
A Nationwide spokesman said: "In the current market, 5% is a particularly good rate. We've also got a similar regular savings account that pays 6% if you've got a Nationwide current account; that really is high."
Many mutuals and ethical providers do consistently better than the big banks for customer satisfaction too.
In a recent survey of members by consumers' organisation Which?, Smile and the Co-operative came second and third, with respective satisfaction ratings of 89% and 86%, after internet bank First Direct on 93%. Nationwide was fifth, with 76%, after The One Account (83%).
Politicians from all parties are supporting Move Your Money. Fifty have signed early day motions backing the campaign and many more have pledged to move their own cash.
East Dunbartonshire LibDem MP Jo Swinson has already taken action. She said: "One way we can all try to bring about change is to send a clear message and put our money where our mouths are by choosing mutual and ethical alternatives to the big banks. I've recently joined the local credit union."
There are almost 500 of these member owned and run co-operatives across the UK. Everyone who joins must share a common bond, such as living or working in a particular area or doing the same type of job but because there are so many unions, most people are eligible for one.
To find your nearest, log on to findyourcreditunion.co.uk or scottishcu.org, or call the Association of British Credit Unions on 0161 832 3694. For more information about the Move Your Money campaign, log on to Moveyourmoney.org.uk.