Consumers could save over £5 million every day - that's a staggering £2billion a year - if they switched away from their expensive credit cards, according to Which? magazine.

The latest piece of switching research follows last month's No Interest campaign encouraging consumers to consider switching their current accounts. The research showed that cardholders would save £2billion a year in interest charges if they switched the £30 billion outstanding on their credit cards, at an average rate of 16 percent, to a card with a rate of 10 percent. And, if customers took advantage of the low introductory rates offered with some cards, the savings would be even greater.

Which? analysed the costs and features of all the credit cards available nationally to find the best value ones and came up with the 'best buys' for cardholders who always pay their bills and for those who use their cards to borrow . Which? showed one cardholder how to save £192 in interest by switching away from his existing three credit cards.

Increasing competition and new card issuers offering lower interest rates have helped to reduce the average card interest rates - and it's easy to switch. A Which? survey last year found that 97 perent of people who switched found it easy to do and nine out of ten of them encountered no problems. So there's no need for people to continue to use expensive credit cards. Credit card companies, including high street banks, are making millions of pounds by charging cardholders high rates of interest and by not passing on reductions on Bank of England base rates.

Last month Consumers' Association submitted evidence to the Treasury Select Committee on banks. Part of the submission questioned why these companies are making extra profit at consumers' expense.

Credit cards give valuable protection when paying for things. The Consumer Credit Act states that the credit card company is jointly liable with the shop or service provider if something goes wrong with a purchase costing over £100. They can also offer additional benefits, including cash back and points, which can be exchanged for goods.

Helen Parker, editor of Which? said: Cardholders are pouring money down the drain by using costly credit cards. People shouldn't be afraid to switch credit cards. Our research showed that almost everyone who switched had no problems at all. And by switching to one of our 'best buy' cards you could save hundreds of pounds a year."