Tesco, the leading UK supermarket chain is to place its customers under the spotlight via their Clubcards.

Thompson Intermedia, a tracker of advertising and Dunnhumby, market researchers are their snooping partners.

Over 10 million Clubcards are in regular use in the UK. The loyalty scheme is one of the most successful ever by a retailer.

Tesco and their partners are to follow the effect of advertising on 40,000 brands. The information garnered from the research will be sold to companies to evaluate effectiveness.