At least three Dutch retail chains are secretly monitoring the behaviour of consumers by using wifi to track them via their mobile phones as they move about the shops.

Technology website Tweakers says the Bas Group, which operates the Dixons, Mycom and iCentre stores, has admitted using the tracking technology and this week has rolled it out in all 160 shops.

Other companies have also looked at wifi tracking, Tweakers says. ProRail has used it in the past, to monitor how passengers use Groningen railway station. And supermarket group Jumbo, which admits looking into wifi tracking last summer, would not say if it had taken the plunge.

Privacy

According to the Dutch privacy watchdog CBP, shops should always inform customers if they are being tracked. The Bas Group does not consider this necessary because ‘all shops use systems to count customers’, Tweakers said.

The system takes advantage of the wifi cards which all smart phones are equipped with and which look constantly for networks to join. Shops use special equipment to pick up each phone’s wifi card, learning its unique ID number and then using this to follow the phone as people move through the shop.

The information is not personalised but shops can use it to cross reference with other data and build up a detailed picture of their customers, Tweakers says.

More on how the tracking works