Banks are charging too much for the use of overdrafts, new research from the Financial Conduct Authority (FCA) has found.
People don't tend to consider the cost of overdrafts when choosing a bank account, leading banks to offer uncompetitive rates, the regulator found.
It added that the costs attached to such borrowing "can be so complex and opaque that even the most astute consumer could struggle to understand what they are paying for".
The study looked at charges incurred on both arranged overdrafts - those agreed in advance with a bank - and unarranged overdafts - where a bank allows a customer to exceed their agreed current account borrowing.
Many customers also use overdraft borrowing as a "habit" once it is made available to them, the FCA said.
The Financial Conduct Authority (FCA) is planning an investigation into 30 million policies sold by insurance companies between the 1970s and 2000.
The inquiry comes amid concern that loyal policyholders are not being given the same priority as new customers and are facing high fees for substandard service. It will include pensions, endowments, investment bonds and life insurance.
The FCA review, which is to begin this summer, is concerned about insurers using returns from so-called "zombie" funds - which are closed to new customers - to pay bills from other parts of their businesses.
A large number of policies also include exit fees that can halve a policy's value if a customer attempts to switch to a cheaper provider.
Clive Adamson, the director of supervision at the FCA, told The Daily Telegraph: "As firms cut prices and create new products, there is a danger that customers with older contracts are forgotten. We want to ensure they get a fair deal."
Research conducted by the Financial Conduct Authority (FCA) suggests outstanding UK consumer debt is estimated at £12.8-15.2 billion, and fees for debt management plans are estimated to be £25 million a year.
Christopher Woolard, director of policy, risk and research at the FCA, said:
The Financial Conduct Authority (FCA) has said it is unacceptable that people struggling to make ends meet are being encouraged to sign up to "unsuitable" and expensive debt management plans.
The regulator, which is set to start regulating consumer credit, said debt management firms must provide consumers with information on where they can get free debt advice as part of the new rules which come into force on April 1.
Firms will also have to pass on significant repayments to creditors from day one of a debt management plan.
The FCA is concerned that too many firms are encouraging consumers into costly fee-paying debt management plans that are not tailored to their needs or to what they can afford when the focus should be on agreeing a sustainable plan or the right solution.
A new crackdown from financial regulators could put a quarter of payday lenders out of business, the head of the Financial Conduct Authority has said.
Martin Wheatley told Radio 4's Today programme:
"I think our processes will force approximately a quarter of the firms out of the industry and that’s a good thing because those are the firms that have poor practices, and for the rest, we want them to improve.”
The Consumer Finance Association, which represents major payday lenders, said its members would co-operate with strict new regulations by the Financial Conduct Authority but urged the City regulator to tackle practices of the "least reputable lenders".
The City regulator said struggling borrowers should be treated "with sensitivity" by payday firms and said that it expects that around one quarter of lenders will decide they cannot meet its higher consumer protection standards and leave the market when it takes over next month.
"There will be no place in an FCA-regulated consumer credit market for payday lenders that only care about making a fast buck," said Martin Wheatley, Financial Conduct Authority chief executive.
The FCA will examine the culture of each payday firm and it will want to see how they communicate, how they propose to help people regain control of their debt, and how sympathetic they are to each borrower's situation.
It is expected to work with lenders to find ways for them to share more up-to-date information about borrowers, to prevent them from handing out loans which turn out to be unaffordable.
The way payday firms treat struggling customers will come under scrutiny by the City regulator, which has announced a new inquiry to see how sympathetic lenders are when borrowers have trouble paying back their debts.
The Financial Conduct Authority, which takes over supervision of the consumer credit market, including payday firms, from April 1, wants to see whether payday firms and other high-cost short-term lenders are putting too much focus on profits rather than consumers' interests.
It is treating the investigation as "a priority" because three-fifths of complaints to the Office of Fair Trading (OFT) are about how debts are collected, and more than a third of payday loans are repaid late or not at all - equating to around 3.5 million loans each year.
The FCA said its new rules should reduce the numbers, but it also wants to see struggling borrowers helped by discussions on the different options open to them rather than "piling on more pressure" by simply calling the debt collectors.
High street bank Barclays faces a £50m fine over claims it acted "recklessly" in its multibillion-pound bailouts from Qatar in 2008.
The Financial Conduct Authority (FCA) accused it of agreeing £322m of secret payments to Middle Eastern investors to secure their support for cash calls totalling more than £5bn at the height of the financial crisis.
Barclays, which contests the FCA's findings, said the fees relate to advisory services over five years.
It is also being probed by the Serious Fraud Office and regulators in the US, and admitted it does not know how much the final cost will be.