Tesco stocks up on inside knowledge of shoppers' lives

Tesco is quietly building a profile of you, along with every individual in the country - a map of personality, travel habits, shopping preferences and even how charitable and eco-friendly you are. A subsidiary of the supermarket chain has set up a database, called Crucible, that is collating detailed information on every household in the UK, whether they choose to shop at the retailer or not.

The company refuses to reveal the information it holds, yet Tesco is selling access to this database to other big consumer groups, such as Sky, Orange and Gillette. "It contains details of every consumer in the UK at their home address across a range of demographic, socio-economic and lifestyle characteristics," says the marketing blurb of dunnhumby, the Tesco subsidiary in question. It has "added intelligent profiling and targeting" to its data through a software system called Zodiac. This profiling can rank your enthusiasm for promotions, your brand loyalty, whether you are a "creature of habit" and when you prefer to shop. As the blurb puts it: "The list is endless if you know what you are looking for."

Dunnhumby's chairman, Clive Humby, offers a few more clues. Companies such as Experian, Claritas and Equifax have databases on individuals and Crucible collects from them all. Any questionnaire you may have completed, any reader offers you responded to, are bought to build up a picture of attitudes and habits. Crucible also trawls the electoral roll, collecting names, ages and housing information. It uses data from the Land Registry, Office for National Statistics and other bodies to generate a profile of the area you live in. Zodiac is employed to provide a more detailed profile. The combination is valuable to many consumer goods firms: dunnhumby generated profits of £4m on sales of £28m in the last year for which accounts are available. Some £12m of business was done directly with Tesco.

( I told you so, Tesco's is becoming Ruined Steel)