OVER the next five days more than 12m people will visit Tesco to stock up for Christmas and the new year.

At the checkout the vast majority will hand over their Clubcard, Britain’s most successful loyalty card. The more they spend, the more vouchers they will receive in February when Tesco rewards its shoppers for sticking with the country’s No1 retailer.

Nobody in retailing underestimates the power of the card: its success undoubtedly helped Tesco to overtake Sainsbury as Britain’s leading grocer.

But it is not just the store and its customers who benefit from it. As they present their Clubcard this weekend the supermarket’s customers are providing valuable intelligence on Britain’s shopping habits — not just for Tesco, but also for the likes of Unilever, Procter & Gamble, Coca-Cola, Nestlé and Gillette.

Nearly 10 years after Tesco launched its Clubcard the company is discovering that the information produced by the scheme could be almost as valuable as the customer loyalty it has created. Clubcard is now a big business in its own right.

Accounts filed earlier this year by Dunnhumby, the marketing firm that runs Clubcard, showed a huge rise in profits and turnover. In the year ending February 2004 Dunnhumby’s turnover increased by 59% from £18.2m to £28.9m and its operating profit by 213% from £1.5m to £4.7m.

Having conquered the UK, Dunnhumby is now turning its attention overseas and selling its services to some of the world’s largest retailers, including Kroger, the American giant that owns 3,700 stores.

This weekend Tesco will be doing more than counting how much you spend — it will examine every item in your basket for more than 40 key characteristics. It may note the time of day you are shopping, how you pay and even how many calories you are planning to consume.

Visit an out-of-town store late at night and the chances are you own a car — a potential customer for Tesco insurance. Buy less than a week’s worth of calories and the chances are you shop at a rival as well.

And if you regularly pay with the same credit card you must be a pretty good credit risk: “No need for any credit checks, sir. Would you like a Tesco credit card?”

Edwina Dunn, who founded Dunnhumby with her husband, Clive Humby, believes the figures the company holds are one of the most powerful ways of tracking and understanding customers.

Want to assess the market for a new brand of environment-friendly washing powder? Talk to Dunnhumby. Want to run a promotion for Pedigree dog food targeting millions of dog owners? Talk to Dunnhumby. Did that television commercial for your soap powder actually work? Talk to Dunnhumby.

“These are the only figures that allow companies really to understand their customers and brands,” said Dunn. “You want to know about heavy users of strawberry Müller Light? We can tell you.”

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