Bar codes are not legally required on product labels, but are required by the major retailers. The system of label bar coding is administered, in the UK, by the Article Numbering Association (ANA). The ANA allocates a 5-digit manufacturer's number to each Company. Two types of bar code are used: 13 digit code or 8-digit short code.

For the 13 digit code:
Digits 1 & 2 indicate the country where the code was issued, e.g. "50" for UK. (not necessarily the country where the product was manufactured)
Digits 3 - 7 indicate the company who produced the product.
Digits 8 -12 indicate the product and size, e.g. "02467" to indicate 415g Baked Beans in Tomato Sauce
Digit 13 is a computer check digit that can be used to confirm that the make up of the whole code is correct.

The 8 digit code is used for small labels where space is not available for the 13 digit code:
Digits 1 & 2 indicate the country where the code was issued, e.g. 50 for UK.
Digits 3 - 5 indicate the company who produced the product.
Digits 6 & 7 indicate the product and size
Digit 8 is a computer check digit

This system of numbering ensures that every product sold has a different number and barcodes can be read by scanning equipment in supermarkets (Electronic Point of Sale or EPOS). The barcode does not identify the price of the product; prices are stored in a computer linked to the barcode scanning equipment.