Mean and nasty. I hope that there will be some supermarkets that make a selling point of not going down that road, and that customer choice to switch to them will mean that the other ones fall in line and abandon the idea.

Next thing to come along will be electronic money set to diminish in value unless you spend it, to keep the economy boiling along.

So far as till prices are concerned there seems to be one company which bizarrely enough seems to go the other way - Wilkos, where half the time they seem to charge lower prices at the till than that shown on the shelf.