Glyn Reece, my Northern correspondent (Penny's in Chester), tells me that the simple ploy of facing your terminal inwards means people will not be able to secretly photograph transactions or to memorise them. You wouldn't think people had memories that good, but Hitendra Patel assures me that some do. Someone recently came into his store in Harold Hill in Essex for a £25 Asda mobile top-up. The bloke then went round the store picking up a couple of things, but then claimed to be Irish and said he wasn't sure if the top-up would work on his dad's phone.

"He didn't have an Irish accent and as soon as he said it, I knew straightaway," Hitendra says.

It took him a few minutes to find the Asda number he needed to report to, but it was too late. The number memorised was 4981 777 80609. Hitendra claims he could have easily memorised that himself (he was once an accountant) as it is only (only!) nine numbers rather than 12, since the three sevens in the middle take care of themselves. Regular readers know how I am with sums, so now I really must have a lie down.