What the country needs is not more houses but fewer people. The nation needs to develop an economic model which will work with a level or, preferably, a declining population.
The amount of space available to build houses is not the issue. What presents the problems id the services and infrastructure needed to support the populus. We have a chronic lack of school places, a health service creaking at the seams, overcrowded transport facilities and energy provision about to give up the ghost with power shortages forecast. All of this is caused by too many people.