Strategic Housing Land Availability Assessment is an essential evidence document defined in the NPPF.  Its apparent purpose is to enforce the implementation of “an objective assessment of land availability” where a local authority is undertaking a Local Plan process.  The NPPF requires a local authority to identify a proven 5-year land supply for its proposed housing development when it submits its draft Local Plan for examination in public by the Planning Inspectorate.  The document should contain maps and descriptions of all plots of land the local authority has identified for housing and commercial development.  It should identify which pieces of land are available for development in years 1-5, 6-10 and 11-15 of the Local Plan.