03What needs to change?

There is no geographic trend to the changes in space per resident over time. However, some of the cities that are already the most cramped for space have seen the little space that they have reduced further. In these cities, the supply of housing has not kept up with demand. Even though their local economies are growing, people are not able to buy more space due to shortages in housing.

Planning restrictions have further warped supply, restricting residents’ ability to increase the amount of space available to them in cities where space is most limited. The previous expansion of PDR, which removed some of these restrictions, had the greatest uptake in these most cramped cities, due to higher demand.

If PDR were expanded to include upward extensions and other ways of adding new floorspace, the uptake would likely be similar to this previous expansion of PDR. More space would likely be added in expensive cities in the Greater South East of England as well as those cities highlighted in the Midlands where floorspace per person is low.

This is what needs to change:

Permitted development rights should be expanded to make it easier to build extensions and new homes. More policies should be introduced to increase the supply of housing where it is most needed. Allowing residents to add more space when they want to is crucial for improving affordability and increasing the amount of space that residents have in the most expensive and cramped cities.

Existing building regulations and design guides should still apply to extensions and new dwellings delivered under permitted development. To address criticisms of some of the homes delivered under PDR, existing building regulations and design guides should apply to any expansion of PDR for upward extensions. These extensions should follow the framework outlined in the recently published national design guide, and minimum space standards should be avoided.

More widely, the planning system needs a much larger overhaul. The most expensive cities have the greatest demand for housing, and new supply needs to be concentrated in these cities to solve the housing crisis. PDR shows that more flexible planning can increase the number of homes in the cities with the greatest need. The next Government should rewire the planning system so that, in principle, once a local plan is in place, residents should be able to build new homes unless the local authority explicitly says ‘no’, rather than forbidding any development until the local authority says ‘yes’.