Call to build on the green belt to 'solve housing crisis'
21 July 2014 Last updated at 14:52 BST
Could building on some of London's green belt land solve the capital's housing shortage?
Sam Bowman, the research director at think-tank The Adam Smith Institute, believes making it easier to redevelop agricultural land will give people more space to live.
The green belt is intended to provide countryside access for urban dwellers and ensure conservation of nature, as well as maintaining agriculture and forestry.
Mr Bowman spoke to Dr Ann Goddard from the Elstree & Borehamwood Green Belt Society.