When George Orwell envisioned the “telescreen” — the TV that keeps constant tabs on its viewers — in 1984, he predicted that governments would use technology to cross the threshold into our private lives.

Confidential documents published by WikiLeaks this week purport to show that the Central Intelligence Agency created its own 21st century telescreen by hacking into smart TVs. You may be watching YouTube or Netflix, not forced military propaganda, but spies are still able to listen into your living room. Developers used vulnerabilities in Samsung TVs to ensure the products would capture conversations even when they appeared to be switched off.

In what WikiLeaks describes as the first instalment of the “largest intelligence publication in history”, the CIA appears eager to exploit the new spying opportunities created by the internet of things — everyday objects that are connected to the web. Market research group Gartner forecasts there will be more than 20bn appliances, TVs and other devices connected to the internet by 2020.