Credit card companies are being told to end sudden rises in charges after Gordon Brown criticised some of them over claims that they were exploiting the vulnerable during the recession.

Mr Brown, who is said to be deeply concerned about the behaviour of some companies, called yesterday for a “new responsible approach” to lending as the companies were summoned to talks with the Government.

Lord Mandelson, the Business Secretary, called on companies last night to pass on rate cuts and treat their customers fairly and sympathetically. He wants the companies to work with the Business Department on how to deal with debt.

A survey of more than 200 cards by Defaqto, a banking research group, found that although the Bank of England reduced its rate to 3 per cent, the cost of borrowing on cards rose to 17.6 per cent and rates on store cards rose to 25 per cent. Mr Brown was said by his spokesman to be concerned that some companies had increased rates by as much as 10 per cent overnight. While many companies behaved responsibly, the action of others was difficult to defend, he said.

Mr Brown indicated that protection for homeowners struggling financially would be tightened. He said it was not acceptable that lenders were still able, in some cases, to repossess the homes of people who defaulted on their mortgage payments without a court order.

A spokesman for RBS said: “Interest rate decisions on our credit cards are not based on Bank of England base rate moves but on a range of factors, including the Libor rate, which is how we fund our money, and this rate has remained particularly high.”