This.
Was saying to the other half whilst stuck in traffic on the m60 yesterday that you can build houses but what about roads, rail, water,gas and electricity supply? Also food production.
Its not just about 5% of land built on, but more reservoirs and treatment plants, wind farms and power stations etc.
Authorities are increasingly strapped for suitable land and more building on flood plains etc doesn't help
We've a population crisis rather than a housing one.