Sky News in England have discovered fake mobile phone masts used to eavesdrop on telephone conversations in London. The International Mobile Subscriber Identity (IMSI) catchers are known as "stingrays" after a U.S. company that makes the devices, which send a signal that tricks a mobile phone into connecting with the stingray, rather than a legitimate base station. In 2011 The Guardian reported that the devices were being used in London, but the Metropolitan Police refused to comment at the time. A 2014 article in The Times of London gave a legal framework for their use. The English authorities are still keeping quiet about the devices, as Freedom of Information requests about IMSI catchers, from Privacy International and Sky News, were refused. Privacy International's Eric King told Sky News: "With IMSI catchers, it's very difficult for them to be used in a targeted manner. In an urban space, thousands of people's mobile phones would be swept up in that dragnet. What they do with that data, we don't know."