Which? research reveals a flood of frustrated customers ready to take advantage of shakeup in current account market

Record numbers of people are expected to ditch their bank in the coming year as mis-selling, poor customer service and a faster switching service persuade them to make the move. More than a quarter have had a problem with their current account, according to research out today from Which?, with a fifth who made a complaint saying it was not resolved satisfactorily.

The findings come as the Post Office shakes up the market with its first current account since the late 1980s, when it sold the state-run Girobank. Virgin Money and Tesco are expected to follow suit later this year, after the launch of long-awaited changes in September to guarantee customers a smooth bank switch within seven days. This will be backed by a multimillion-pound TV, radio and press advertising campaign and is being endorsed by the chancellor, George Osborne, who wants to see “new faces on the high street”.

Laura Willoughby, chief executive of the MoveYourMoney.org.uk campaign, said: “This will be a big year for switching, partly because of the faster switching service but also because of the new entrants expected to shake up the market.” Last year 1.2 million people switched current accounts – up from 600,000 in 2009 – but this is still only 2.5% of all customers. According to YouGov research, 14 million would be more likely to switch if it was easier. The new rules mean it will only take seven days – instead of three weeks now – and automatically sweep money wrongly sent to the old account into the right one.

According to the Which? research, Bank of Scotland, Barclays and the Co-operative Bank had the highest proportion of complaints, while First Direct and Nationwide had the least. The survey, based on conversations with 2,000 customers, also ranked the biggest banks for customer satisfaction. All did poorly, with Halifax scoring the highest satisfaction of 38% for its complaint handling and Santander the worst, with 30%. Banks’ attitudes towards complaints were also revealed. A Lloyds TSB customer said: “They were rude and made me feel small for daring to question their level of service.”

There were 323,000 complaints about current accounts reported to the Financial Conduct Authority (formerly the FSA) in the first half of 2012, with the figures for the next six months due to be released tomorrow.

At the start of this month, new rules came in that aim to put an end to banks and building societies mis-selling paid-for current accounts. The authority said some customers had been throwing money “down the drain” by paying monthly fees for accounts with add-ons such as travel or mobile phone insurance or car breakdown cover, which turn out to be useless to them.

“Banks are going to have to up their game,” said Kevin Mountford of moneysupermarket.com. “There could be an interesting 12 months ahead.”