The Government has rightly made densification of cities a key policy priority and has set out several proposals in recent months, including a City Densification Fund and new planning reforms through the National Planning Policy Framework.
This policy attention is welcome. Recent Centre for Cities research found that British cities have a ‘density gap’ of 2.3 million homes across their urban cores compared to their French and Japanese peers. The density gap is largest in the big cities outside London and is a likely cause of their economic underperformance.
This research uses data on historic neighbourhood age and Centre for Cities’ residential densities dataset to dig deeper into where densification needs to occur and what policy needs to do differently.
The report finds:
Post-war neighbourhoods explain why the urban cores of the largest big cities such as Manchester, Liverpool and Birmingham are unusually low density. Post-war policy worked to reduce densities in inner urban areas for many decades. These low-density neighbourhoods close to city centres should be prioritised by local and national policymakers for densification.
Recent development within cities has barely exceeded the density of pre-existing neighbourhoods. The major exceptions are high-rise development in the very centres of big cities and targeted densification in London.
Policy to increase densities has struggled as it has rarely targeted neighbourhoods with the greatest potential for redevelopment. Despite efforts to support brownfield development, the planning system has often set minimum densities that are too low. Local and national leaders will need to vary planning policy by neighbourhood to enable widespread densification.
To achieve its goals on densification, the Government needs to continue work on planning reform to move towards a more spatial, rules-based planning system, and continue support for regeneration, including of existing residential areas.
Measures to achieve this include:
Funding should be made available for the regeneration of low-density post-war neighbourhoods in the urban cores of the largest cities. This should be a part of the upcoming Northern Growth Strategy.
The National Planning Policy Framework should require local authorities to designate urban cores, and recent proposals for national minimum density policies should be amended.
Mayors should use Spatial Development Strategies to introduce London-style density matrices to set expectations that densities should increase and vary according to connectivity to city centres.
Mayors should use new powers in the English Devolution Bill to establish Mayoral Development Corporations and Orders to densify urban neighbourhoods.
Local authorities should establish minimum and maximum building heights in all parts of the urban core, and introduce Croydon-style suburban intensification policies.
National government should continue its bold reforms to increase the viability of urban development, including through site threshold reforms, to enable cash, rather than on-site, affordable housing contributions, and by removing Biodiversity Net Gain requirements on brownfield sites.