There are approximately 470,000 Listed buildings in England and Wales.
It is sometimes surprising to find out why a building is Listed although on obtaining a copy of a Listing from the English Heritage it may be found that, fortunately, the building is Listed for historical rather than architectural reasons or that only part of the building is Listed such as an internal staircase or ceiling design.
In general, the higher the level of Listing, the higher the level of protection.
Also, it must be borne in mind that if a Listed building is within the vicinity of a proposed development site, the local Planning Authority may hold that proposals touch or affect this Listed building, hence a potential reason for refusal