So the UK population is not the complete set of entities that want to buy housing stock, and measuring population alone is not sufficient to capture the entirety of the demand. This means we need to build even faster! Saturate these markets. Those folks are giving us money to build empty houses; use it! Once supply outstrips all demand, prices fall - that's how markets work. Let the invisible hand of the free market inform the foreign investors that housing bubbles are a bad bet. Certainly nothing else has worked.