My Northern correspondent, Glyn Reece (Penny's in Chester), writes that a "respectable matron of the village" tried to pass a 'dodgy' £20 a while ago. He automatically rejected it and she cried: "How do you KNOW it's not real?"

"Well," says Glyn, "when you handle as much money as I do in a day, you get the 'feel' of it. If you doubt me, take it to a bank and let them examine it."

His customer said: "I'll take it to Sainsbury's, they'll accept it."

"Of course, they will," he replied, "because their staff haven't got a clue, neither do they care it's not their business."

It's a good point.