Will London become the world's first National Park City?

Environmentalists call the lack of exposure to green spaces for urban-dwellers as "nature deficit disorder". But there is an ambitious proposal underway to connect Londoners to green spaces, by turning the city into a national park. The man at the heart of the idea is geographer Dan Raven-Ellison, who spoke to Dan Damon on the rooftop of the BBC building in central London.

(Picture: Aerial view of London, showing large green spaces Credit: Octopi London)