Travel sustainability of new build housing in the London region: Can London's Green Belt be developed sustainably?

Although London's high-density compact city planning has largely delivered sustainable development in the urban core, the wider regional challenge is that housing targets have been consistently missed for the last decade, and the lack of supply is exacerbating the housing affordability crisis. Releasing Green Belt land has been cited as a solution. This paper analyses new build development in the London region from 2011 to 2022, and confirms that Green Belt policy needs reform – local authorities in the Green Belt have the lowest housing delivery in the region, and car dependent ‘leap-frog’ development is occurring beyond the Green Belt boundary. The relaxation of Green Belt restrictions could greatly boost development, but would also risk producing car dependent housing. This research produces a new Travel Sustainability Index using census travel behaviour data, and analyses the travel patterns of residents in new build housing over the last decade. The conclusions are that more sustainable Green Belt development can be achieved by prioritising development in Outer London and through extending existing towns and cities in the Greater South East. Achieving this outcome will require improved regional planning coordination and infrastructure investment. • A decade of housing development tracked using Energy Performance Certificate data. • Travel Sustainability Index created to measure sustainability of new build housing. • Green Belt authorities have the lowest housing delivery in the London region. • Greater London development sustainable but will continue to miss overall targets. • Green Belt development can be more sustainable by expanding existing settlements.