Brownfield sites are on paper the great opportunity for housing development. UK cities are distinctly lacking in density when compared to European and world cities . Some of this is about our dislike of building up but  much is about the inability to get brownfield sites going.  This register of 1,000,000 homes planned suggest a real opportunity to densify effectively although this has sometimes been done without proper infrastructure investment , often linked to the differing objectives of the  multifarious arms of government that need to buy into that investment. Its also another clear piece of evidence that ultimately if housebuilding remains solely in the hands of developers and builders we can never build what we need for social purposes.  the private sector needs to maintain its margins. Flooding  the market with new builds won't do that. Councils need to build social housing. Its an open goal . the Government cannot afford to miss it- otherwise its good intentions on housing will not be delivered.