Before 'chip & pin', a customer paying for goods in a shop with a credit or debit card would confirm the card was theirs by signing a paper receipt. Then the shop assistant would compare this signature against the signature on the card. But this system was not very secure: if someone lost their card, it was fairly easy for a thief to forge their signature, by simply copying it from the card.

A new idea was proposed: a new kind of card would be made, with an electronic computer chip embedded in it. The customer would prove that they were the cardholder by entering a secret 4-digit PIN number (Personal Identification Number) on a keypad.

As with most changes in technology, some people were worried at first that their money would not be safe using the new system. In 2003, a thousand shopping outlets in Northampton tried out the chip and pin system for three months. It was the first such trial in the UK, designed to get the public's reaction to it, and to check whether the technology worked. After three months the public voted it a success and it has been in use ever since.