Most customers will no longer be able to make a credit or debit card purchase with a signature from today, as the new chip and pin system becomes fully operational.

The system, which requires costumers to use a pin number instead of their signature, is aimed at combating fraud.

Disabled cardholders and those with cards from overseas will be allowed to sign for goods. 

Customers with cards that are not chip and pin-enabled - or 4% of the four million cards in circulation here – will also still be able to pay by signature.

Those with new cards who do not know their pin are advised to contact their bank.