Many people have been paying off credit card debts
Interest rates on credit cards are at their highest level for 12 years, according to research by Moneyfacts.
The financial information service said that the average rate has risen steadily to 18.8% in February, despite the main Bank rate remaining at 0.5%.
Card providers have pushed up rates owing to fears that borrowers are more likely to default.
But recent Bank of England figures suggest the situation is not so acute, with rates at a three-year high.
Figures from the Bank of England revealed that there had been a huge rise in the amount of money that banks were writing off as bad debts on their credit cards.
This indicates that the main reason for rising credit card interest rates is the jump in borrowers defaulting on their debts.
This has led to a widening of the difference between these rates and the Bank of England's Bank rate, which has stood at 0.5% since March 2009.
The Bank's figures showed that write-offs doubled to £1.6bn in the third quarter of 2009, as banks acknowledged that this money would never be repaid by defaulting borrowers.
In each of the two preceding quarters, the figure had been about £800m. It totalled £3.2bn during 2008.
This has been reflected in the Bank of England's figures that show the average interest rate on credit cards offered by banks and building societies has risen to its highest level since June 2006.
At the end of January, the rate was 16.4%.
However, the Moneyfacts figures show that the typical credit card interest rate level is higher, at 18.8%.
This may be because the Moneyfacts figures show the current quoted rate from providers charted on its database, whereas the Bank of England looks retrospectively at the interest rate charged in the previous month.
Fears over defaulting borrowers have pushed up rates
It has proved much more difficult for borrowers to switch their debt to another card for a better deal.
"The UK continues to suffer from a high level of unemployment and providers are worried about the increased risk of customers not repaying their debts," said Michelle Slade, of Moneyfacts.
"This increased risk continues to be passed on to both new and existing credit card customers through higher rates."
She said that a borrower with £5,000 debt on a card, who repaid the minimum each month, would now repay an additional £2,289 over the life of the debt than they would have in February 2006.
The Finance and Leasing Association (FLA) said that some people's interest rates had dropped.
"Lenders must price responsibly in a challenging market and ensure that, so far as possible, the rates they charge reflect the risk they face. That is why some customers have also seen their interest rates fall," said Fiona Hoyle, of the FLA.
"It is also important to recognise that the average APR figure from Moneyfacts excludes 0% deals on purchases and transfers and does not take into account rates for existing customers."
Andrew Hagger of financial website Moneynet said: "With the UK suffering from a surge in unemployment and the potential of more job losses to come if public spending is curtailed, just as with unsecured personal loans, it is no surprise to see rates remain stubbornly high."
He warned that some credit card lenders could change the interest rates on existing debts.
Government proposals, published in October, include stopping card firms changing interest rates on existing debts and suggesting the minimum amount that must be paid off each month should be increased.
But this brought a strident response from the credit card industry in January, which argued that only 8% of customers were offered an unsolicited increase in their credit limit in 2009.
The UK Cards Association said that customers had 30 days to turn down such an offer, so the practice should not be banned except for those facing financial difficulties.
It argued that in 40% of cases, the interest rate was lowered, and the practice allowed card providers to be flexible. It said customers could opt out of any interest rate changes.