False mobile phone towers are being used by British police to spy on citizens, a media investigation has uncovered.

These fake towers are known as Stingrays (or IMSI catchers to give them their less catchy official title), and they work by tricking your phone into connecting when you stroll within range. Once connected, the masts can be used to listen in on your conversations.

Stingrays are used by police across the globe to spy on criminal types, but the controversial masts also collect the private communications of anyone else in the area.

Sky News launched its own investigation into whether UK police were deploying Stingrays to spy on suspects and found that over 20 of the devices were being used at the time. The Stingrays were detected using specialist software by German firm GMSK Cryptophone, which pick up on a Stingray’s activity from close range.

The CEO of Cryptophone said: “The abnormal events that Sky News had encountered can clearly be categorised as strong indicators for the presence of IMSI catchers in multiple locations.”

The Met Police have declined to confirm Sky News’ findings, despite prior reports that it paid almost £150k for the Stingray tech. However, Met commissioner Bernard Hogan-Howe commented:

“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. If people imagine that we’ve got the resources to do as much intrusion as they worry about, I would reassure them that it’s impossible.”

Although Stingrays do intercept communications from innocent bystanders as well as criminal targets, the police are unlikely to be interested in what you thought of last night’s Geordie Shore or random mutterings on how Cathy was proper smashed last night. Of course, anyone rocking a tin hat collection could also argue that this is just one more step towards non-stop nationwide surveillance.