Jeremy Boot has a keen eye and an interest in vintage townscapes. He wrote to us of the largely forgotten practice of putting telegraph poles at rooftop levels in large cities. At some point this ceased, he told us, presumably as more and more cables were laid underground. Here's a couple of examples he pointed us to. Credits to Nottingham Archaelogy twitter feed for the first and to flashbak.com for the Picadilly Circus photo. You have to squint to see the pole in either pic.