In research released by MoneyExpert, some 30 million people (about two-thirds of the adult population) claim to be "in the dark" when stating the level of charges incurred for being overdrawn. Meanwhile, even those who had successfully campaigned against their financial services provider for unfair fees were unable to accurately say how much they had originally been charged.

Sean Gardner, chief executive of MoneyExpert, said: "Bank charges may be a hot topic in the media but many people's idea of how much they are being charged for their overdrafts is horribly wide of the mark." He added that by not being conscious of charges, such financial ignorance could see Britons develop further difficulties in managing their money.

"Going overdrawn can be costly. Average unauthorised overdraft interest rates are around 25 per cent and fees for going in the red without permission can be as much as 30 pounds. It's critical that people check with their bank to ensure they are borrowing money at a competitive rate," Mr Gardner commented.

The study also showed that an estimated five million Britons wrongly believe that overdraft rates are more competitively priced than secured loans. Just over a third (35 per cent) of those consumers surveyed who actually know what their authorised overdraft rate is claim to only pay five per cent interest when going overdrawn - cheaper than the rate available on the best personal loan currently on the market. Meanwhile, 32 per cent claim that they are paying out between five and ten per cent.

However, the financial services provider suggested that in reality banks are charging an average of 12.35 per cent for going into authorised overdraft limits. Yet this figure was only flagged up by 12 per cent (or 1.7 million) of respondents.

Research from MoneyExpert also revealed that Britons are ignorant of the level of charges they receive for exceeding their overdraft limit. Some 18 million consumers were said to be completely unaware of the costs incurred by their bank, as 5.5 million believe that they are hit with fees of under 20 pounds. However, in reality the typical charge was said to be 28 pounds.

As a result, Mr Gardner pointed out that those consumers unhappy with their financial services provider should "consider jumping ship". He added that there are various methods of borrowing, such as secured loans, which are "considerably cheaper" than going into overdrafts.

However, those who opt to take out a personal loan as a way of supplementing their finances could be well advised to keep up with their monthly repayments. Earlier this year, research carried out by MoneyExpert showed that an average of 7,700 loan repayments have been missed every day during the first six months of 2007 - a total of 1.38 million. Mr Gardner claimed that despite their finances continually being stretched, those borrowers who fail to make payments risk damaging their credit rating and going to court.