'Zombie Bank Accounts Cost Savers £4bn A Year'
Savers are losing more than £4bn a year by having their money in poor-paying accounts, according to consumer group Which?
The group found more than a third of accounts closed to new customers, dubbed 'zombie accounts', paid 0.5% interest or less.
This compares with the best-paying Isa savings accounts which offer up to 2.75%.
Three-quarters of people surveyed thought banks did not do enough to help savers get a good deal.
Which? also found more than a third of people had not switched their main savings account because they did not think it would make a difference.
The group's analysis suggested there was a difference of £4.3bn a year between the amount savers would have received if they were all paid the average interest rate and the amount they would have received if they all had money in a top-paying account.
According to Which?, 82% of the 1,999†easy access savings accounts and cash Isas on the market in March were zombie accounts.
Nearly four in 10 (39%) of those accounts paid 0.5% interest or less and 16% paid 0.1% or less.
Which? said the savings market could be "confusing", with some accounts paying very different rates of interest despite having similar names.
It wants banks to move people's money into one default easy access or Isa account at the end of fixed terms.
Which? executive director Richard Lloyd said: "With many savers never switching because they don't think it will make a difference, savings providers should do more to help their customers get the best deal.
"They need to be clear about interest rates, let people know when bonus rates come to an end and make it easier for people to switch Isas."
Andrea Leadsom, the economic secretary to the Treasury, said: "The Chancellor announced a number of measures to help and support savers, notably increasing the cash Isa limit to £15,000, at this year's Budget.
"These changes will give savers more flexibility and choice."