Bath residents are being tracked by Bluetooth technology without their knowledge.

As part of a University of Bath research project that's designed to study how people move around cities, more than 10 Bluetooth scanners were placed in offices, cafes, shops and pubs throughout the city. The scanners track residents by communicating with Bluetooth-enabled devices such as smartphones and laptops.

There are thought to be some 1,000 of the scanners throughout the world after Cityware, the team behind the technology used in the experiment, made the software available through websites including Facebook and Second Life.

According to Cityware, the scanners are not able to personally identify individuals.

Eamonn O'Neill, director of Cityware said: "The objective is not to track individuals, whether by Bluetooth or any other means. We are interested in the aggregate behaviour of city dwellers as a whole."

However, the project has raised a number of privacy concerns and the Information Commissioners' Office said it was "monitoring" the experiment.

Residents that don't want to be spotted by the scanners can simply turn their Bluetooth signals off.

See also: Intel launches Bluetooth-killer