This week, I found out about a concept called “right to light”:
Right to light is a form of easement in English law that gives a long-standing owner of a building with windows a right to maintain an adequate level of illumination. The right was traditionally known as the doctrine of “ancient lights”. A right to light can also be granted expressly by deed, or granted implicitly, for example under the rule in Wheeldon v. Burrows (1879).
via Wikipedia
This sounds quintessentially British and then I discovered that it had serious ramifications for the BBC when building their HQ in London:
The site of Broadcasting House was initially to be developed as what were described as “high-class residential flats”, however the location was perfect for the BBC. It offered a central London location, close to multiple transport links, and with just enough space to construct a new building.
The owners of the site agreed to build the BBC’s new centre and offered a long lease, however the BBC purchased the site before the building opened.
The site was of some size, but was strangely shaped, with a long curved section along Portland Place. The building was limited in height as there were a couple of nearby buildings that had their right to light protected under the custom of “ancient lights”.
via A London Inheritance