Dr Rio said: “They actually don’t need to decrypt traffic, because they can already see the packets. They have control over the iPlayer, so they could ensure that it sends packets at a specific size, and match them up. They could also use directional antennae to ensure they are viewing the Wi-Fi operating within your property.”
Privacy campaigners described the developments as “creepy and worrying”.
A spokesman for Privacy International, the human rights watchdog, said: “While TV Licensing have long been able to examine the electromagnetic spectrum to watch for and investigate incorrect usage of their services, the revelation that they are potentially developing technology to monitor home Wi-Fi networks is startlingly invasive.”
A spokesman for TV Licensing said: “We’ve caught people watching on a range of devices, but don’t give details of detection as we would not want to reveal information helpful to evaders.
“Our use of detection is regularly inspected by independent regulators.”