A shopper passes a retail store advertising a sale in Oxford Street, London Reuters

Retailers in the UK can now track the shopping habits of customers through smartphones and facial recognition software programmes that allow them to use a shopper's journey to learn how they use the store. The Information Commissioner's Office said that shops can track customers using Wi-Fi on their mobile phone and "MAC address which can be linked to a specific individual".

The technology is open to all and may already be in use at airports, train stations and other transport hubs. Some city-wide Wi-Fi networks are also connected to facial recognition software that increase accessibility of user data and make digital tracking more accurate.

"This technology, which is starting to be rolled out in shops, allows retailers to use the customer journey to build up a picture as to how people typically use the store. It uses the MAC address of a smartphone which can, in many cases, be linked to a specific individual," Simon Rice, the group manager for technology at the Information Commissioner's Office (ICO). He suggested that retailers may use the tracking technology to make changes to store displays or product prices to increase footfalls and encourage repeat customers.

The technology is similar to that used in online advertising, where software programs create a behavioural pattern for users and target adverts accordingly. The data privacy and protection watchdog warned that smart CCTV cameras enabled with facial recognition software track and identify people, enabling retailers to target adverts accordingly in stores, The Guardian reported. Stores can use this technology to target adverts of cosmetic products for women or male grooming products for men.

The technology falls under the purview of ICO as it relates to utilising individuals' private data. The watchdog is currently working as part of an international collaborative initiative, on forming guidelines for data protection in telecommunications that will make the use of this technology more transparent.