The policy explains that the TV set will be listening to people in the same room to try to spot when commands are issued. It goes on to warn: “If your spoken words include personal or other sensitive information, that information will be among the data captured and transmitted to a third party.”

The warning applies to TV viewers who control their Smart TV using its voice activation feature.

Such TV sets ‘listen’ to every conversation held in front of them and may share any details they hear with the Smart TV company or third parties.

Mr Huntley said he had first come across the issue in October when he had begun researching how his LG Smart TV had been able to show his family tailored adverts on its user interface.

Digging into the TV’s menu system, he had noticed that an option called “collection of watching info” had been switched on by default, he said.

“It’s actually worse, I think, than if they’d not offered the opt-out in the first place since it allows the user to believe nothing is being sent.”

He had then attached an external hard drive to the TV’s USB slot, expecting that the screen might simply report that he had been watching material from an external device, he said.

Instead he had found the name of each media file stored on the drive – including photos labelled with his children’s names – had been sent back to LG.