People will be left "cupping their hands over their mouths" in the street if new lip-reading CCTV is not reined in, the Government’s surveillance watchdog has warned.

Tony Porter, the Surveillance Camera Commissioner, said in future people would have to guard their conversations from prying cameras in the same manner as football managers on live TV, unless ministers act to regulate emerging intrusive technologies.

The commissioner, who has been in place since 2014, also warned that doing nothing could see Britain become a Big Brother-style state that went beyond anything envisioned by George Orwell in his dystopian novel 1984.

Among the new technologies Mr Porter expressed concern about were lip-syncing programs that can decipher what people are saying at distance as well as gait-analysis software, which can identify an individual just by the manner of their walk.

“The capability to run lip-sync technology to determine what people are saying would have a very suppressive effect. It would change the nature of our society,” Mr Porter told the Evening Standard. “People wouldn’t feel they could have a conversation outside. We increasingly see the football manager cupping his hand over his mouth to give instructions for fear of being exposed.

“Just extrapolate that by millions and what it would mean if people knew there was a capability of walking down the town and your lips moving could be picked up and extrapolated into a conversation.”