SSSIs in the UK are notified using the concept of an Area of Search (AOS), an area of between  and  in size. The Areas of Search were conceived and developed between 1975 and 1979 by the Nature Conservancy Council (NCC), based on regions created by the Local Government Act 1972.
SSSIs in the UK are notified using the concept of a Search Area (SA), an area of between  and  in size. The Search Areas were developed between 1975 and 1979 by the Nature Conservancy Council (NCC), based on regions created by the Local Government Act 1972.