By drawing upon McAuslan’s analysis of the ideologies underpinning land use planning law, this paper examines financial viability modelling and legal processes in the context of local authority decision-making related to property development on large urban sites. A local authority can make a site ready for development by using ‘compulsory purchase’ powers to acquire land, by transferring that land to a property developer and by granting that developer planning permission to commence construction. Analysis of case law, academic criticism of viability modelling practices and a recent property development project highlights issues arising when local authority planning departments use viability appraisals to legitimise decisions purportedly taken in the public interest. An in-depth examination of viability modelling within local authority estates departments then opens a new site for critical inquiry of local authority land acquisition practices. The paper’s conclusions reflect upon how financial viability modelling shapes decision-making despite questions surrounding both modelling techniques and the outputs that viability appraisals produce
