indeed, some of it was/is. However in london it was (mostly) slammed in on bombsites/ex industrial places: https://www.insidehousing.co.uk/news/council-releases-map-of...

southwark has the most council estates. the further out boroughs did try and put their estates far out. Places like thamesmede (https://en.wikipedia.org/wiki/Thamesmead) failed because there was literally nothing else around (thats improved significantly, 50 years later)