A charity has demanded card firms are banned from raising the credit limits of customers without permission, claiming those struggling with repayments are more likely to be targeted.
Citizens Advice says the practice has hit almost one in five borrowers struggling with long-term debt – accusing lenders of carrying out poor affordability checks.
It released its report covering the activities of card providers at a time when regulators worry that consumers and banks alike may be getting out of their depth.
Officials are particularly keen to avoid any credit bubble bursting.
Unsecured borrowing – buoyed by low interest rates – has been growing much faster than household incomes at an annual rate of more than 10% this year.
Figures released last month showed the total was back at its financial crash level above £200bn – with a third of that figure on credit card balances.
However, there has been a noticeable slowdown in lending since the Bank of England’s intervention – which also coincided with the Brexit-linked slowdown in the UK economy.
Statistics published by the Bank on Wednesday showed unsecured borrowing rising at its lowest annual rate since April last year, at 9.8% last month though total credit card balances continued to rise to almost £69bn.
Citizens Advice said it had helped nearly 66,000 people with over 140,000 credit card debt problems over the past year.
It cited several examples of bad practice including the experience of one man who owed £15,000 on four different credit cards.
The charity said that despite only making minimum repayments on each card which covered the interest, he was notified by all four providers that they were increasing his credit limit with his bill eventually hitting £30,000.
The Financial Conduct Authority has proposed that people with persistent debt have their cards suspended to help them get to grips with the problem and avoid further charges.
Citizens Advice chief executive, Gillian Guy, said: “The regulator must ensure that lenders are taking into account people’s whole financial and personal situation before agreeing further credit.
“Banning firms from raising existing customers’ credit limits without seeking their express permission first would also help people take more control over their finances.
“Lenders must act responsibly and direct people struggling with debt towards free and independent advice and support – rather than more credit.”