Over the past year, the watchdog has seen a 75% surge in the number of complaints about these accounts, which include extras such as mobile phone, travel and identity insurance, the Daily Mail reports.

A fifth of current account holders are signed up to these deals. Many customers were lured into opening them by commission-hungry branch staff.

But for many the perks have proved to be useless. Others were secretly switched from free accounts – only realising once they had forked out hundreds of pounds.

The Financial Ombudsman says it is receiving around 70 complaints a week about the accounts, compared with 40 the previous year.

Common complaints include those from customers whose accounts were automatically switched to paid-for deals without realising. Others were not clearly told how much the account would cost or were simply unable to claim on any of the perks.

Under rules introduced earlier this year by the Financial Conduct Authority, banks are now forced to check whether customers are eligible to claim under the accounts.