Stingray fake phone masts placed around London to listen in on all calls

More than 20 fake phone towers, which indiscriminately hoover up information from phones, were found

The BT Tower

More than 20 fake phone towers, which indiscriminately hoover up information from phones, have been found active in London.

The controversial technology is supposedly used to catch the communications of criminals, by intercepting information on its way to the network. But they’re unable to distinguish between the phones of criminals and everyone else, meaning that they pick up all of the information that is sent through them.

There are over 20 at work in London, according to a Sky News investigation, and it’s unclear who is operating them.

The Stingrays, also known as IMSI catchers, work by tricking phones into think that they’re phone masts. When phones connect to them, they are able to pick up all of the data that is flowing through them, but the people using them would have no idea that it is happening.

Police around the world are thought to be using the technology. But this is the first time that they have been found in the UK.

The Metropolitan Police was reported in 2009 to have bought some Stingrays, and in November the Times said that the police had started using them. But Sky News’s investigation is the first evidence of their use.

The Met would not confirm or deny that it was using the technology, telling Sky News that “the only people who benefit are the other side, and I see no reason in giving away that sort of thing”.

The director-general of the National Crime Agency told Sky News: "Frankly, some of what we need to do is intrusive, it is uncomfortable, and the important thing is we set that out openly and recognise there are difficult choices to be made."

But the technology can also be bought easily and relatively cheaply on the internet, meaning that some or all of the use found by Sky News could be from criminals or other non-governmental people.

“When will Police stop pretending IMSI catchers don’t exist?" said Eric King, deputy director of Privacy International. "The spying tool has featured in everything from ‘The Wire’ to ‘Zero Dark Thirty’. Companies are selling them on the grey market to anyone who can pay.

"The only thing we don’t know about them, is what the police are doing to protect people from their use by criminals, and when they use them, what legal frameworks ensures they’re properly used?"

Sky News located the masts using technology made by GMSK Cryptophone, a German security company. The organisation found the more than 20 fake towers in three weeks of use.