Increasing density is a key way of delivering more homes where land supply is constrained. London Plan Policy 3.4 aims to ensure that development optimises housing output for different types of locations in London and has an associated sustainable residential quality (SRQ) density matrix (London Plan Table 3.2) which sets ranges for appropriate residential density in different urban character settings and with different levels of public transport accessibility.
However, the majority of recent developments in London are being delivered at densities beyond those recommended in the density matrix. In addition, density can be measured in different ways. As part of the full review of the London Plan it is necessary to assess the nature of the development the current policy approach is delivering and consider if an alternative or amended approach is required to deliver sustainable development in London. This evidence will be provided by five interlinked research projects: (1) Measuring and defining density, (2) Lessons from higher density development, (3) Affordability, development and costs and viability, (4), Exploring character and development density, and (5) Why else is density important?.
The general brief for this particular project – embodied in the question ‘why else is density important?’ – involved examining significant respects whereby maintaining/raising the density of development and intensity of space-use might be important in relation to London Plan objectives. More explicitly, the brief asked for identification of the linkages between urban form, agglomeration economies and overall economic productivity, and their implications for density policies that might enhance productivity. Taking an extended view of productivity, allowing for environmental externalities also, the report similarly examines the significance of the linkages between urban form, travel patterns and (carbon) emissions. A third topic specified in the brief is that of how density policy may enhance the effectiveness of new housing initiatives in relation to starter homes and PRS – for which denser sites offer specific productivity advantages for those housing types which could secure the supply of key types of worker to sustain high productivity levels in London’s economically dynamic sectors.