The naga, originally from Bangladesh, was developed commercially by Michael Michaud, who runs a specialist online chili supply firm in south-western Britain. Having spotted it in an ethnic-food shop in the coastal town of Bournemouth, he bred a dependable and much hotter strain and had it tested. "I sent the powder to a couple of labs. They didn't believe the reading. They thought they had made a mistake," he recalls. Jonathan Corbett, the buyer who handles (cautiously) specialist chilies for Tesco says that the naga makes a standard hot curry "taste like a bowl of breakfast cereal".

The naga has been a runaway success. In 2007, a Tesco outlet in Newcastle in northern England was supplied with 400 packs for a pilot period that was intended to last a month. The entire stock sold out on the first morning. According to AC Nielsen, a market-research firm, demand for hot chilies across all British retailers rose by 18% in the last year. At Tesco, the growth has been 29%. Demand for the naga has been so high that it has been forced to sell unripe green ones, intended for sale early next year. Tesco's supplier is Britain's biggest chili farmer, Filippo Salvatore. Based near Biggleswade, he is also a leading light in the Bedford Sicilian Association. He is hurrying to grow more.

Tesco is one of the world's largest retailers, with outlets in both continental Europe and North America. But Mr Corbett says that his colleagues have no plans to stock the naga elsewhere, for example in the firm's Fresh & Easy chain in America. "Tastes in the UK are hotter," he says. That may be true, though the chili-eating milieu is certainly bigger in America, where the calendar is dotted with events such as the rumbustious Fiery Foods and Barbeque Show (in Albuquerque) and the more academic 19th International Pepper Conference (which took place in September in Atlantic City, concluding with a barbecue).

... contd.