He told Panorama about GCHQ’s “Smurf Suite”, a collection of secret intercept capabilities individually named after the little blue imps of Belgian cartoon fame.
“Nosey Smurf is the hot mic-ing tool, so, for example, if it’s in your pocket they can turn the microphone on and listen to everything that’s going on around you”.
Mr Snowden who was responsible for the biggest leak of intelligence documents in history is now a fugitive in Russian Federation.
The former NSA contractor flew to Moscow two years ago, and faces United States charges that could land him in prison for up to 30 years.
He said the text message sent by GCHQ to gain access to the phone would not be noticed by its owner.
Other programmes used by GCHQ were nicknamed “Tracker Smurf” and “Dreamy Smurf”, which allows phones to be switched on and off remotely, Snowden said.
“When it arrives at your phone it’s hidden from you”.
The BBC said the government had declined to comment in line with usual policy on intelligence matters. “But we haven’t gotten much further than that”.
Asked if he would be prepared to do a deal with USA prosecutors he said: “Of course, I’ve volunteered to go to prison with the government many times”.
Once GCHQ had gained access to a user’s handset, Mr Snowden said the agency would be able to see “who you call, what you’ve texted, the things you’ve browsed, the list of your contacts, the places you’ve been, the wireless networks that your phone is associated with”.
Critics have long argued that Snowden harmed national security with his disclosures, but supporters believe that his actions were heroic. Mark Giuliano, the deputy director of the Federal Bureau of Investigation, has called Snowden a traitor. “I gave all of my information to American journalists and free society generally”.
“I have paid a price but I feel comfortable with the decisions I’ve made”. “If I’m gone tomorrow, I’m happy with what I had”.