Facebook's Portal smart home device is finally launching in the UK – but a human contractor might end up listening to your voice commands.

The device, whose AI-equipped camera will follow users around the room in order to keep them in the frame during video calls, will be available to British consumers for the first time from Oct 15.

Users will be able to make voice calls using Facebook Messenger and encrypted voice calls using WhatsApp, as well as watch Facebook's TV service in tandem with their friends.

But Facebook admits up front that clips of the instructions given to Portal's voice assistant might be passed to human contractors to check whether they have been correctly interpreted by its speech recognition software – unless users explicitly opt out.

Andrew Bosworth, Facebook's vice president of augmented and virtual reality, said that Portal would never record the content of anyone's video calls, and that its "smart camera" software remains entirely on the device without any data being sent back to Facebook.

"Getting the right people to help review voice transcripts makes the service a lot better," said Mr Bosworth.

"It makes it more inclusive. People have subtly different accents; people have slightly different word usage or might not have access to a technology that you and I might take for granted.