[2008] EWCA Civ 861, 29 July 2008. An assessment of the economic viability of local authority affordable housing targets are a crucial element of planning policy guidance. By failing to carry out an assessment and instead relying on an earlier housing needs survey, the local authority had acted outwith its powers. Appellant local authority appealed against an earlier decision that quashed the affordable housing quota set out in its core strategy. The authority had set this figure at 30%, based on a survey carried out some two years earlier. The original inspector had concluded that the new guidance (Planning Policy Statement 3) (PPS3) had not affected the needs of the core strategy set out, but he should have realised that the local authority were liable to carry out a detailed economic assessment of the economic viability of its target. Held: appeal dismissed. The main issue was whether or not the inspector should have found the core strategy compliant with PPS3 based on the evidence provided. The inspector should have found that the earlier housing needs survey used a broader, incorrect definition of affordable housing and that, as a result, the core strategy missed the quotas required by PPS3. The process leading to the adoption of the affordable housing policy was found to be legally flawed and the local authority were found to be acting outside of the appropriate power.