The Tesco Clubcard was surely one of the greatest marketing ideas of all time. Launched in 1996, the loyalty card now has some 10 million subscribers and spawned a multitude of copycats.

A clever PR stunt put the Clubcard back in the news yesterday. According to the Daily Mail, some more astute shoppers have noticed that the value of Clubcard points earned on a purchase is sometimes more than the cost of the purchase itself. As a result, one person went and bought himself 10,148 ready meals. They cost him £6,596, but earned him £20,296 worth of points. Even after paying for a van to take the meals to a homeless shelter, that's still a nice little earner.

Other people don't quite seem to have got the hang of it. Another shopper bought 924lbs of bananas (which I calculate is a staggering 2500 of them) in order to make a profit of, wait for it, £24.64.