StingRays are small boxy devices that can mimic the signals sent out by cell towers. Since phones are designed to automatically connect to the nearest and/or strongest tower, mobile devices tend to link to StingRays in places where they've been deployed. Once connected, the surveillance box can collect various data, such devices' identifying information, subscriber names, phone numbers, call times and duration, among other things. Yes, it connects to almost every phone in an area where it's stationed and collects data from all of them. More advanced StingRays can even listen in on conversations or see text messages.

According to Privacy International, the devices are deployed in the UK under Police Act 1997 Part III, which regulates the installation of bugs in a target's home. That particular police act has nothing to do with mobile phone interference, which means it's impossible to tell how many times law enforcement approved StingRay use in the country. The London police also refuses to directly admit that it's been using StingRays for years. When asked about it, Met commissioner Bernard Hogan-Howe told the Sky News: "We're not going to talk about it, because the only people who benefit are the other side, and I see no reason in giving away that sort of thing."