Around a quarter of cardholders in the UK are putting their money at risk by using the same PIN number for all their credit and debit cards, according to research commissioned by price comparison Web site Moneysupermarket.
The research found that, of the 41 million adult cardholders in the UK, 9.84 million - 24% - use the same PIN for all their cards.
The research, which is based on online polls of 2018 and 2002 UK adults conducted by Opinium Research, also found that 11 million people who have tried to be cautious by having different PINs for each card, now find themselves not using at least one of them because they can't remember the card's PIN.
"After going to the trouble of choosing and opening an account, I'm shocked that 11 million of us have stopped using a card because of a forgotten PIN," says Steve Willey, head of credit cards, moneysupermarket.
MoneySupermarket also warns that seven million cardholders - 17% - are putting themselves at risk of cloning and skimming by letting their card go out of sight when making a purchase.
"A little vigilance can go a long way. It certainly beats the trauma and trouble that can be caused by being far too lax with your cards," says Willey.