Nearly one in five people struggling with debt have had their credit card limit raised without request, according to research from charity Citizens Advice.
It comes as the Bank of England has warned in recent months about credit card debt and is looking to crack down on irresponsible lending by banks.
Consumer borrowing has risen to more than £200billion with more than a third of this figure on plastic.
Problem debt: Citizens Advice says banks should not increase credit card limits automatically without request from borrowers
The data from Citizens Advice shows that 18 per cent of struggling credit card users had their limit raised in the past year without requesting it, compared to 12 per cent of all credit card holders.
The charity would like the practice banned without banks obtaining explicit consent from customers to give them more protection against ever increasing debt.
It wants the Financial Conduct Authority to provide clear guidance to lenders stressing that before increasing a borrower’s limit, they must check their ability to repay it.
It says poor affordability checks by firms are making people’s financial situation worse.
Citizens Advice has helped nearly 66,000 people with over 140,000 credit card debt problems in the last year.
Gillian Guy, chief executive at Citizens Advice, said: ‘Irresponsible offers of further credit are pushing people into long term debt cycles.
‘It’s clear that irresponsible behaviour by some lenders is making people’s debt situation worse – such as offering more credit when they already have thousands of pounds of unpaid debt.
‘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.’
Dan Wass, director of banking and insurance at Nationwide Building Society, said: ‘We support Citizens Advice in calling for an end to credit card firms raising credit limits without expressly getting permission from the customer first.
‘Allowing customers to decide whether or not they receive an increase to their credit card limit not only helps them stay in control of their money, but could also prevent them getting further into debt.
‘Nationwide is the only provider that always asks customers to opt in rather than automatically apply increases to credit limit.
‘We believe it isn’t fair to assume someone would want or need greater access to credit, so in March 2016 we changed our terms and conditions to rule out auto credit limit increases, although this had been our policy for a number of years.’
People with credit card debts are also more likely to get into long term debt than those with personal loans and are less able to pay their debt down, the research indicates.
Only 60 per cent of those struggling with credit card debt were able to reduce it over two years, compared to 72 per cent of people struggling with a personal loan.
One pensioner Citizens Advice helped was repeatedly called by firms offering more credit cards – despite the fact that she could only afford to make minimum repayments on her existing cards.
She used the cards to meet her essential bills and ended up with a total of 21 credit cards and debts totaling £70,000.
Another man the charity helped owed £15,000 on four different credit cards, but despite only making minimum repayments on each card which just covered the interest, he was notified by all four providers that they were increasing his credit limit.
He turned to Citizens Advice for help when his debts hit £30,000.
The FCA has announced a range of proposals to help those already in long term credit card debt – who are spending more on credit card interest charges than paying off the total amount they owe.
It says lenders should contact customers who have been in this situation for three years to arrange a plan to pay their outstanding balance more quickly.
Citizens Advice says lenders should be asked to intervene sooner – at the very latest after two years – to help people struggling with unaffordable debt.
This is Money warned earlier this year that annual credit card spending had grown at its fastest pace since before the financial crisis, prompting fears of a credit-fuelled bubble.