I want to know why new housing is unheard of over there
A full answer would be long and complex, but here are the main points:
Firstly, the acute shortage of land for new housing; coupled with the strong opposition of local communities to further urbanisation of what remains of the British countryside, and national planning regulations which in any case make it difficult to build on these 'greenfield' sites. (The previous Labour government had zoned large areas of the country for new housing: but this was immediately axed by the new Conservative government, who are, however, in the process of liberalising the planning laws - to much opposition from within their own party).
Secondly, the shortage of credit is making it more difficult than ever for first-time buyers to enter the housing market, despite recent falls in house prices which remain among the developed world's highest.
Thirdly, the private rented sector, as an alternative to owner-occupation, is smaller in Britain than in any other western European country, and there are currently no economic incentives for new investors to enter this market.
Finally, government spending cuts have removed almost all funding for not-for-profit Housing Associations to build new social housing for subsidised rental.
Thanks for the boots on the ground.
Well, they were really stupid to open up the country to gazillions of immigrants, then!