Despite controlling the majority of the population's day-to-day finances, the UK's big five banks only appear nine times in the top 64 Best Buy credit cards, loans and savings accounts list issued by consumer magazine, Which?

But, despite their apparent lack of enticing offers the big five have a stranglehold on the country's finances, illustrated by the percentages of customers holding accounts with them. Almost 65% of credit cards, 53% of savings accounts, 50% of personal loans and 45% of ISAs available in the UK financial services industry are operated by the big five.

In addition, the consumer magazine says that the level of service offered by the big five is often lacking and they suggest that not only can customers get more competitively priced products elsewhere, but also a better level of service by switching to smaller, more customer-focused organisations.

As a result, the magazine's editors are baffled by the loyalty to the big five. It would be understandable to pay higher prices if the trade-off was that the level of service was exemplary, but according to Which? customer service is not one of the banks' strong points. They carried out three major pieces of research looking at customer satisfaction with current account providers, mortgage lenders and credit card companies. The results were pretty damning for the top five in all categories.

Which? say their research highlights how little research the majority of consumers conduct when they opt to take out new financial products. For example, many of the best credit cards in terms of interest rates and balance transfer offers are not operated by the top five banks, yet almost seven in ten of UK credit card holders still choose to stay with the big five.

The same principle applies with current accounts where the top five operate 79% of the country's total accounts despite paying an average of only 0.1% in interest against the market average of 1.78%.

So, it appears that when it comes to banking and credit cards options customers are more willing to go with a big bank than to go with the best deal. There are many reasons why customers choose to stay with the big five, but one of the most easily understandable is inertia. People are more likely to get a divorce than change their current account, so when the banks' marketing material hits a customer's doormat or pings into their email inbox, it's more likely to be taken up than other forms of unsolicited junk mail.

However, despite attempts from Which? to highlight better offers elsewhere, the big five look set to continue their market domination as the British public loyally support them.