He wrote: "Barcode is a means of numeric/alphabetic data entry which replaces a manual entry onto a till via an epos terminal. Using a combination of thick and thin bars (binary level), or a combination of the widths of black bars and white gaps (spaces), the data is submitted through the decoding scanner. Just like the family name and the first name, 'Universal Product Code' allocates unique numbers to every product."
Blimey. The code consists of digits for the name of the country (the United Kingdom has the digits 500-509), so once an item goes through the till you can tell whether it's from Moldova (digits 484) or Albania (digits 530).
Then there is a code for the manufacturer, an item code and then a single 'check digit', designed to prevent errors.
"A code therefore might read: 501 [UK] 0356 [John Dickinson] 75006 [Lion Brand 150-sheet notebook]
6 [check]. And every barcoded product in the world has its own unique number."
Glyn also points out that the country code indicates the country that issued the code and is not necessarily the country of origin. For example, a bag of salad may contain leaves from several different countries but if it was packaged in Britain if will have the 500-509 digit flag. These finer points are obviously becoming more important in these carbon-footprint-conscious times.
But, I asked Glyn, has anyone ever asked him about barcodes?
"Nope," he says, but adds, "but they are an excellent thing if you have epos, because everything about epos is good. There's no guesswork at the till. There are no arguments about price."