Which? in call to cut financial firms' phone charges
Financial firms have been urged to cut the cost to people calling their customer service or complaints lines.
A study by consumer group Which? found that almost three quarters of such lines were costly 084 or 087 numbers.
The British Bankers' Association (BBA) said it expected many of its members would switch to cheaper call rates for complaints in the near future.
Which? called on the Financial Conduct Authority (FCA) to act to stop the use of high-rate complaints line numbers.
It also said the FCA should extend these regulations to cover customer helplines.
Which? said that 177 out of the 242 lines it surveyed were 084 or 087 numbers.
The firms using these numbers included many of the UK's leading High Street banks and building societies.
They included HSBC, Lloyds Bank, Nationwide and TSB Bank, credit card providers American Express, Capital One and Tesco Bank and insurers Aviva, Churchill and Direct Line, said Which?.
A survey of more than 2,000 people for the watchdog group suggested that 39% preferred the telephone as a means of making an enquiry to a financial firm, and 31% would use the same contact method for a complaint.
Which? found that 95% of credit card providers in the study used the more expensive prefix numbers, as did 89% of current account providers.
The EU Consumer Rights Directive will ban the use of expensive numbers for customer helplines from next year but financial companies are excluded.
Barclays and Barclaycard have announced they will offer a freephone or basic rate number for all customer helplines.
NatWest and RBS will have cheaper phone lines for customer enquiries by the end of this month.
'Let off hook'
Richard Lloyd, executive director of Which?, said: "Millions of us prefer to deal with our bank on the phone, yet we are expected to cough up for a costly call when we do.
"We applaud Barclays and Barclaycard for breaking from the pack on high rate numbers and want to see other financial firms follow their lead.
"It's not right that financial companies are being let off the hook. The FCA must act now to put an end to costly calls in this sector."
He added: "It's great news that NatWest and RBS are doing the right thing for their customers by dropping costly calls."
Ashok Vaswani, chief executive of Barclays Retail and Business Banking, said the telephone was the most convenient way of contact for many of its customers.
A BBA spokesman said: "All banks are actively looking at how they can reduce costs for customers.
"We expect to see many banks changing to use local numbers for complaints in the near future and it is good to see that some banks have already committed to doing so."