A survey of 1000 UK adults by financial services marketing consultancy Teamspirit found that on average consumers have two PINs - one for a debit card and one for a credit card - and a further eight passwords and user names to memorise. But over 20% of respondents said they have twice as many.

Only 60% of respondents could remember two access codes unprompted, with the figure falling significantly when people were asked to remember more.

According to the survey, over 50% of people use the same PIN number for at least two cards, and in some cases every card had the same number.

Jo Parker, MD, Teamspirit, says: "There is a serious risk that the security of personal financial information could be compromised by the user employing the same digits across a number of services. It is certainly best practice not to do so."

Parker says consumers are even resorting to writing down security codes and PINs, with eight per cent of respondents keeping the details next to their credit cards in a wallet or purse: "We encountered occasions where a respondent had actually written the PIN number on the signature slip on the reverse of the card because they were so often forgetting it."

Furthermore, separate research conducted by Saga Visa Card shows that the problems some consumers experience recalling PINs is having a knock-on effect on the way in which they use plastic payment cards.

According to this study, over three quarters of people have different PINs for each of their cards, and the introduction of Chip and PIN technology has led one in seven people to stop using one or more of their cards.