Once upon a time,  not so very long ago...
Most villages were served by a Unit Automatic Exchange rather like the one in the photograph.
Unit Automatic Exchange buildings were sometimes faced with red brick, but often locally available materials were used and much effort was made to match the surrounding architecture. Thus these small buildings tended to blend into the rural landscape and could be quite unobtrusive. They were designed to operate without intervention for long periods. Over the years, many events conspired to bring about the demise of the local rural exchange:-

•   A greater concentration of population requiring larger exchanges.
•   Improved line plant leading to longer lines.

•   More linked-numbering schemes, bringing about the loss of exchange name identities, making it easier to absorb a nearby exchange into a larger one.
 Typical Switchgear that would have been installed in a UAX
The Old Telephone Exchange at Mamhead had been decommissioned, empty and vandalised for many years before eventually being sold at auction in 2007.
After a protracted battle with the local Planning Department, and with the active support of the villagers of Mamhead, permission was finally granted in 2009 to convert the derelict building into a holiday cottage.  The auction and conversion was filmed and featured in the BBC Homes Under the Hammer series
An extension was built onto the front of the old exchange to enlarge
the kitchen space, with a second, smaller addition at the front to provide a wetroom.  The whole building was reroofed, rewired, replumbed and redecorated to create the bijou holiday cottage that you see today.
In order to take advantage of the spectacular views, two sets of patio doors were added to the rear of the building, where previously there had been no windows at all.  To complete the conversion, the roof and cavity walls were insulated and all windows double glazed, before the final addition of the wood burning stove.

Recently, a sleep shelf with a double futon mattress has been added to allow two additional people to sleep with a view of the open countryside.