SSSIs are a national selection of sites providing statutory protection for the best examples of the UK's flora, fauna, or geological or physiographical features.
These sites are also used to support other national and international nature conservation designations such as Special Protection Areas (SPAs).
SSSIs are notified under the Wildlife and Countryside Act 1981. Improved provisions for the protection and management of SSSIs were introduced by the Countryside and Rights of Way Act 2000 (in England and Wales).
There are eight SSSIs in the Lee Valley Regional Park.