These policies are known as "saved" policies. Legal requirements of all local development documents They should be prepared in accordance with the local development scheme and should have regard to : National policies and advice contained in guidance issued by the Secretary of State, The regional spatial strategy for the region in which the area of the authority is situated, if the area is outside Greater London. Also the RSS for any region which adjoins the area of the authority or the Wales Spatial Plan if any part of the authority's area adjoins Wales The spatial development strategy if the authority is London borough or if any part of the authority's area adjoins Greater London The community strategy prepared by the authority and also any other authority whose area comprises any part of the area of the local planning authority Any other local development documents which has been adopted by the authority The resources likely to be available for implementing the proposals in the document Such other matters as the Secretary of State prescribes. They should comply with the statement of community involvement (once the statement is adopted) The local planning authority must appraise the sustainability of each development plan document and report the findings. Development plan documents are subject to rigorous procedures of community involvement, consultation and independent examination. Once adopted, development control decisions must be made in accordance with the DPDs unless material considerations indicate otherwise. DPDs must be examined with a sustainability appraisal to ensure economic, environmental and social effects of the plan are in line with sustainable development targets. Key government aims Flexibility Strengthening community and stakeholder involvement Front-loading sometimes – local authorities to take key decisions early in the preparation of local development documents. Sustainability appraisal Programme management Soundness – local development documents must be soundly based in terms of their content and the process by which they are produced. The must also be based upon a robust, credible evidence base. Criticism In practice, many local authorities have found Local Development Frameworks difficult to implement. Although progress on Local Development Frameworks was made in the years 2012–2015, an assessment by Nathaniel Lichfield and Partners has found any progress to be "marginal". See also Development control in the United Kingdom London Plan Planning and Compulsory Purchase Act 2004 Planning Policy Statements Town and country planning in the United Kingdom References External links Government Website on PPS12