THE typical bank customer could save up to £15 a month by swapping their current account, yet only 3 per cent have done so in the past year and 40 per cent have never moved.

Watchdog the Competition and Markets Authority (CMA) says that personal customers would, on average, be £92 a year better off with a new provider, while overdraft users going into the red for one or two weeks every month could typically save £180.

Since seven-day switching was introduced in 2013, more than three million account holders have moved - just over a million of them in the past 12 months. Many more have stayed put, however, and could be suffering for their inaction.

Three-quarters of accounts pay no interest on credit balances and this proportion is likely to rise since the Bank of England cut its base lending rate to a new low of 0.25 per cent earlier this month.

Meanwhile, nine out of 10 charge an account or overdraft usage fee and some apply both. Moneyfacts.co.uk says that the average usage fee for an authorised overdraft stands at an all-time high of £6.93 a month, or £83.16 a year.

Charges for unauthorised borrowing have fallen in recent years, but UK banks still make a total of £1.2bn from this each year.

Rachel Springall, the information provider’s finance expert, said: “Traditionally, providers charged interest when customers dipped into the red. However, more are opting to charge flat usage fees on top or in replacement of this.

“This is a result of the banks aiming to offer greater transparency, but in most cases the cost of dipping into the red has become extortionate.”

In a bid to help customers, the CMA announced earlier this month that by early 2018 account providers must at least set a maximum monthly charge and alert customers who are about to go over their borrowing limit.

It also said banks must make it easier for account holders to share their data securely with other banks and third parties, making it possible to manage their finances through a single app.

The watchdog said these improvements would make it simpler for customers to compare accounts, which it hopes will encourage more to switch.

Online comparison website Gocompare.com already allows users to compare the ‘midata’ associated with their online bank account to find out how much they could save by moving. Midata creates a file of deposits, withdrawals and charges from 12 months’ worth of statements.

Matt Sanders, the website’s head of money, said: “The free-to-use service, which is still the only one of its kind, uses customers’ midata files from their online banking service to securely calculate the best current account for them based on how they actually use their account.

“The results are displayed showing how much better off they could be in pounds and pence if they moved their account. This service takes all of the guesswork out of finding the right current account.”

Mr Sanders added: “To date, the banks have not gone out of their way to promote this service or make it easy for customers to access their own data and transfer it to the midata comparison tool. Clearly they have a vested interest in keeping hold of their customers for as long as they can.”

With so few accounts paying interest, high charges widespread and Santander announcing that it is slashing the benefits payable on its market leading 123 account from November, it is understandable that many people fear it won’t be worth switching.

Santander 123, which costs £5 a month, will now pay a flat rate of just 1.5 per cent interest on balances up to £20,000, down from a top rate of 3 per cent, but this is still considerably more than most accounts are currently paying.

Other accounts paying above-average interest rates include Nationwide’s FlexDirect, which requires a minimum monthly deposit of £1,000. It pays 5 per cent interest on balances up to £2,500 for 12 months, later dropping to 1 per cent.

TSB’s Classic Plus, which requires a £500 monthly deposit, pays 5 per cent on up to £2,000, plus 5 per cent cashback on the first £100 of contactless purchases each month. Tesco Bank, which has no minimum funding requirement, gives 3 per cent interest on balances up to £3,000. There are also Clubcard points on debit card spending.

Meanwhile, Halifax Reward, which is offering a £100 incentive to switchers using the seven-day service, pays £5-a-month tax-free if you deposit at least £750, use two direct debits and stay in credit. It also gives up to 15 per cent cashback on selected spending.

To use midata to find out which account would be best for you, simply log onto your bank account, download your midata file, which is likely to be listed under a heading such as “account services”, and drop it into Gocompare.com’s comparison tool.

Case study

Carol Nicholas and her husband Anastasios both switched from standard no-interest current accounts to TSB’s Classic Plus earlier this year.

The retired nightclub owner from Glasgow said: “We were in the bank one day and one of the staff pointed out that we weren’t getting any interest. I thought it was par for the course these days, but he suggested we move to Classic Plus.”

The account pays customers who deposit at least £500 a month 5 per cent interest on the first £2,000 of their balance. For the next year, it is also giving 5 per cent cashback on the first £100 of contactless payments every month.

Mrs Nicholas said: “I didn’t want a big palaver, but the switching process was no trouble at all, and now we’re earning interest we wouldn’t otherwise have got.”