Why are buildings listed?
Buildings are ‘listed’ because they are considered to be of special architectural or historic interest and as a result require special protection. Listing protects the whole building both inside and out and possibly also adjacent buildings if they were erected before 1 July 1948. The prime purpose is to protect the building and its surroundings from changes, which will materially alter the special historic or architectural importance of the building or its setting.
All buildings erected prior to 1700 and substantially intact are listed, as are most buildings constructed between 1700 and 1840, although some selection does take place. The selection process is more discriminating for buildings erected since 1840 because so many more properties remain today. Buildings less than 30 years old are generally only listed if they are of particular architectural or historic value and are potentially under threat.