Saw this article a few days ago, thought it was worth re-posting:
"Britain's oldest working television has been tracked down in a house in London.
The 1936 Marconiphone is thought to have been made in the months that Britain's first "high-definition" television service began.
The set belongs to Jeffrey Borinsky, an electrical engineer and collector of antique television and radio sets.
He bought the set, which has a 12-inch (30cm) screen from another collector 10 years ago and is still working on restoring it to its original state.
The screen is mounted inside a wooden cabinet. The image from the cathode ray tube, mounted vertically inside the cabinet, is reflected onto a mirror.
The few controls include volume and vertical hold, but there is no channel changer, as there was only one channel when it was made: the BBC."
Oldest TV in UK BBC link