Chip and PIN deadline
After 14 February some retailers may refuse to accept payment from people using chip and pin cards if they do not know their pin number.
During the introductory period of the chip and pin system, retailers have been able to accept a signature after first checking with the card issuer.
After 14 February, banks and retailers have decided to curtail this facility.
Consumer groups say that many disabled people find it hard to remember their pins and may be turned away at tills.
The Association of Payment Clearing Services (Apacs), which has overseen the chip and pin programme, said people who had forgotten their pin numbers should ask their card provider for a new one.