Pinpoint accuracy informs the art of the new soft sell

There is an information revolution taking place in Britain that will allow advertisers and retailers to know not only what we buy and where we buy it, but also where we live, what our credit rating is, if we are alcoholics or whether we like Greek ewe's cheese.

A combination of computerised mapping software, census data, loyalty cards and supermarkets becoming banks is giving the marketing industry the unprecedented opportunity to observe how we live, what we buy ... and then to change it.

The advertising agency International Poster Management, which includes among its clients Imperial Tobacco and Tesco, is offering clients maps of postal-code areas - which can be as few as 14 houses - colour coded to show the occupants' preferences from vodka to airline destinations or life-assurance policies.

One airline client wanted to promote its new fares to Bangladesh, so IPM constructed a map using census data that showed, street by street, where all the Bengali-speakers in London lived. A small poster campaign, written in Bengali, was then booked in those areas.

"Smirnoff didn't know who bought their vodka in Scotland," Chris Morley, chief executive of IPM, said. "Now we can target advertising to a particular stronghold just east of Glasgow and to the commuter routes people who live there use on their way to work or the shops."

The quest to crawl over every inch of consumer behaviour leads to some odd sights. Poster companies recently funded a study by Birkbeck College that used a special headset which observed the dilation of the subject's pupils to calculate what attracted their eyes in the street, including, of course, advertising hoardings and brand names.

Not content with knowing what we look at when we are out and about, the same study questioned 10,000 people about their travel patterns, so advertisers could catch them when not in front of the television.

When you are in your home they know who you are and who you are with. Programme makers and advertisers were told at the weekend at The Television Show conference in London that the image of the nuclear family sitting together in front of the television is rapidly going out of date. Only 35 per cent of viewing now takes place with another person, because of the rise in multi-television homes. The study of viewing, by the research company RSMB/DGA, could even tell that young families and retired people were the ones watching on their own the most. It found that the fastest- growing market for sales of television sets is for children's bedrooms. And they can pinpoint what kind of family, whether single-parent or with young or old children, is likely to be doing the buying.

We are the ones adding to the biggest jump in the marketing industry's knowledge of us. In the past two years we have filled in application forms for 20 million loyalty cards issued by supermarkets. The applications give only name, address and age but the supermarkets can build up a much fuller picture of us very quickly.

They pass on information to massive data banks about what we buy, when we buy it and where we live. "The loyalty cards are more about getting data than just giving loyalty points," Sean Brierley, deputy editor of the business magazine Marketing Week, said.

The idea is that big consumers of, for example, pet food can be targeted specifically through the post with special offers or free samples.

But this is just the beginning. Last month Sainsbury launched its own credit card and Tesco will soon follow. Chains of retailers such as Dixons and Shell are linking together in card schemes that will amass detailed information about our lives. Once we start using the credit cards issued by supermarkets they will know our income, our credit rating and, crucially, when we are not shopping with them.

"The potential is huge," said Mr Brierley. "They can identify people who regularly buy nappies and send them special offers for other baby products. Or they make the connection that you won't be going to the movies much with a young baby, so through the post comes an offer on videos.

"At their most sophisticated, the supermarkets can cross-match all sorts of consumer preferences to encourage you to take up new ones: for example, they find that people who buy olives and feta cheese usually buy Californian wine. If you've been buying the olives and cheese but not the wine they send you an offer on Californian wine, because they think you should like it and you should be buying it."

Behavioural research and tracking by big businesses far outstrips the funding for academic social studies research. And the use it is put to is moving us away from a mass of anonymous consumers to small, tightly defined groups whose tastes and choices can be minutely described, predicted and, most important of all, influenced.