'Stingrays' Covertly Monitoring Mobile Phones in the UK

VOICED: Fake phone masts could be intercepting your calls and text messages. The devices known as 'stingrays' covertly monitor mobile phones, and Sky News has learned that it's unclear who is operating them. Shows treated aerials of London residential streets and street scenes from London and New York City, as well as a press conference with Metropolitan Police Commissioner Bernard Hogan-Howe and Director General of the National Crime Agency Keith Bristow. Interview with barristerTim Johnston. (Contains black hole - third party material.)