Are high street shops secretly tracking your movements through your phone?

Privacy concerns have been raised after it emerged that a number of major high street chains are tracking customers using their mobile phones.

Marks and Spencer, Dune, Topshop and Morrisons are among the stores using technology to keep tabs on shoppers using a small white box, usually fixed to the ceiling, which is constantly gathering data provided by your phone.

They are using a new technology that picks up the signals your phone gives out as it searches for a Wi-Fi network to join.

This allows them to track the number of customers in and out of the shops and also builds a picture of how customers move around the shop itself. This data is then used to redesign the store layout to make it easier to get around – or to steer you towards specific goods.

It also allows retailers desperate to make sales to push special offers to your phone as you shop. At some Westfield outlets, the Telegraph reports, the technology can tell if you check the price of a certain product in another store, allowing rivals to lure you back with personalised offers.

You may even have agreed to this tracking without noticing – many free in-store Wi-Fi networks require you to agree to lengthy terms and conditions that you’ve probably never read.

Within these Ts&Cs you may have agreed to give retailers access to your search history, or permission to be tracked around the store.

Privacy campaigners don’t think that shops are doing enough to let people know how their data is being used.

“It’s a huge problem, and most people don’t even know that their own phone is being used to monitor them,” Renata Samson, chief executive of Big Brother Watch, told the Telegraph.

“Shops will say they are just trying to make the experience more personalised and better, but why aren’t there signs warning people that it is happening, like for CCTV?

“When you login there need to be explicit opt-in procedures so people know what they are signing up for and can say whether they want their data to be used for analysis.

“Not only is it an invasion of privacy but it’s a security risk. Nobody knows how safe these networks are, and who is to say that the wi-fi network you join is legitimate.”