What is a ‘regular’ customer? That was the short, intriguing question on my answer phone. I rang Mahesh Patel to ask what he meant. Turns out he might be my Sherlock, although in reality he runs a store called Yogi Smurti in London’s Shepherds Bush.

Regular readers will have been aware of the saga of the Vodafone voucher scam. For those who don’t know, it goes like this: bloke comes into store, shops around, asks for top-ups (displaying ready cash to pay for them); retailers do not put the vouchers anywhere within sight, but do process them. ‘Customer’ leaves store to consult with someone in a car outside regarding purchases, but never comes back. Disappears sans shopping, sans vouchers. Retailer rings to cancel voucher, but Vodafone says flog to next customer. But voucher doesn’t work says next ‘regular’ after they take it away to try. So they get a refund.

My Sherlock detects conspiracy. The next person to come into the store is that regular customer, because that’s the way the two have planned it. ‘Regular’ takes voucher away and reports back that it is useless, although it wasn’t really. And this all happens so fast it appears to be a cyber crime – except store has no wi-fi.

Does the retailer ever see that ‘regular’ customer again? Perhaps the best thing to do is to network with other retailers, because an embedded regular will have a chain of stores they visit to ‘buy’ top-ups.