The law of Ancient Lights means that any building in England which has been in place for 20 years can put up a notice which reads 'ancient lights' to ensure that the light coming into the building isn't affected by a new building being built too close.
It dates from the 13th century, but was updated by the 1832 Prescription Act, and can apply to trees as well as walls, although it doesn't apply to the loss of a view.
It works: court cases have been won against those who have blocked out the light to a neighbouring house.