Ping! We know where you are, and people who will pay us to tell.

What is pinging?

Mobile phone networks have the ability to locate their customers' handsets (pinging). At a basic level, they can determine which cell the phone is using. In a city, that might narrow-down the location to a few hundred metres. In the countryside it could be several kilometres. It is also possible to triangulate the position of a phone more precisely using its relative position to several masts. Additionally, many modern phones contain GPS technology to help determine their exact longitude and latitude.

Mobile operators are reluctant to discuss exactly what level of detail they are able to provide to law enforcement, although there are examples of police tracking criminals, accident victims and missing persons by their mobile phones.

A former News of the World journalist's allegation the newspaper paid police to track mobile phones raises serious questions about the UK's eavesdropping laws, according to experts. Sean Hoare said it was possible to "ping" a handset's location for £300. (more) (DIY Ping) (How to)