A new Royal Town Planning Institute (RTPI) study, undertaken by Heriot-Watt University and consultancy Three Dragons, combined analysis of data about the housing market and housing supply in the South West with an investigation of six case studies of large-scale developments in the region.
According to the report, the case studies - which ranged in size from 650 dwellings to around 8,000 - were chosen to represent a range of locations, values, site types and scales and stages of development.
The case studies are Bath Western Riverside (Bath); Charlton Hayes (South Gloucestershire); Cranbrook (East Devon); Monkton Heathfield (Taunton); Sherford (Devon); and Tolgus (Redruth).
The report says that promoting a set of larger sites for additional development through the planning system "may lead to improvements in general housing market affordability as well as potential significant additions to the affordable housing stock".
"Overall, we can say that promoting a set of larger sites for additional development through the planning system should lead to improvements in general housing market affordability, particularly for first- time buyers and in the medium to longer term," the report says.
But the study adds that it is not the case that new-build market housing on larger sites is itself particularly affordable. Instead, it says, the general increase in supply progressively improves affordability, while such sites "enable the delivery of significant additions to the social housing stock, so long as section106 obligations can be applied at a significant level".
The report’s modelling indicates that house prices in the housing markets where the case study projects are located would be lower by between one and eight per cent by 2021 and by between two and 15 per cent by 2031 than they would be if the schemes were not built.
These masterplanned developments could also increase the stock of local affordable social housing by up to 50 per cent, the report suggests.
But it warns that the contribution offered by these sites was largely produced through strategic planning processes that have now been abolished, and that urgent steps are needed to find new ways of bringing forward new large sites.
Delivering large-scale development requires leadership, skills and approaches that are likely to be unfamiliar to many local authorities, it says. These include masterplanning, resolving land ownership and viability issues, negotiation with developers throughout the scheme’s life, and the time and ability to strike funding deals.
RTPI head of policy Richard Blyth said: "The experience of the last 20 years shows that piecemeal incremental developments alone will not meet the level of demand for new homes. We must therefore ensure there is proper, long-term planning and delivery for housing on a large scale.
"However, the Housing White Paper hasn’t really addressed the critical issues facing large sites. It asks whether planning procedures should be streamlined to ‘support innovation and high-quality development in new garden towns and villages’. Our report shows that we need more, not less, planning to get large sites right without the delays and compromises we see so often."