This document discusses the need for new housing in the UK and issues around where to build new homes. It notes that the government set a target of building 4.4-5 million new homes between 1991-2016 but only around 2 million have been built so far. It explores options for where to build, including greenfield land, greenbelt land, and brownfield sites. It also discusses the aims of greenbelts and issues around building on greenbelt land, as well as development pressures on rural areas like those around Cambridge.