This is what being a telephone engineer involved in 1930s London.
Twice a year the steel wires which support London's telephone cables - each cable may hold the lines of thirty subscribers - are inspected.The cables are fastened to the wires by rawhide suspenders, and this man is detaching the thick dark cable from the old wire and fastening it to the new wire, which shows fresh and bright above.
This new wire also supports the worker. He sits in a "bo'sns chair" consisting of a board slung by a loop at either end, which is fastened to the wire. Overhead wires are gradually being superseded by underground systems.
There are more vintage photos of London, dogs, street scenes, transport, all sorts, on my Facebook page, to see them all you have to do is "Like" the page and you don't even need to be sincere to do so!
Contemporary photos are on my Flickr photostream.