A law of nature deriving from these checkout complaints is that even the most modern technology is utterly thick. I mean, just because the bar code on my bag of carrots is a bit scrunched up, I have to wait for a supervisor (if one can be located at all) to authorise the sale, often by going the half-mile back to the veg dept to get a bag that'll scan. I can't just say to the cashier "they're 85p, those," can I? Not allowed! The system can't cope with it!* And while I'm at it, why does a 67-year-old buying a bottle of wine at a self-service checkout have to wait for a supervisor to confirm that I'm over 18? Put a rudimentary camera in the bloody thing!

*Although there's one wizened old cynic at a supermarket near me who, after repeated failed efforts to scan something, hands it to me and says "Here, just put it in your bloody bag..." No names, no pack drill!