In the 1970s, it was usual for working class newlyweds would have to live with their parents until they were able to find housing. That's why second-rate comedians of the time like Les Dawson had so many mother-in-law jokes: there was an awful lot of resentment between young men and their mothers-in-law to exploit. There's nothing new about multiple families crowding into houses designed for just one family in this country - that's why there are so many pubs.

The Town and Country Planning Act 1947 has been identified as a cause of insufficient housebuilding activity, and new legislation is currently working its way through the House of Lords to alleviate this.

In the UK specifically the radical reform (read destruction) of council housing by the Thatcher government had a large impact on the housing market in the 1980s.

Afaict Housebuilding will not improve based on current legislatory changes, not even close. Until you murder land value capture nothing will change.

In 1970 you could basically buy any non-city plot of land and build a shack on it without anyone bothering you. Think of the back to the land hippies in California just chopping down trees and starting their little communes -- they'd be utterly fucked if they did that now, some Karen would rat them out instantly to planning and zoning committee.

In the late 60s/70s DIY builders were almost completely displaced by developers who lobbied for regulations that stomped out "a guy and his pickup truck" by and large almost anywhere with desirable land. Then the owners of those houses reinforced same to prop up their property values.

I live in one of the last remaining counties that didn't do that, and last year I built a house for $60k. Pretty easy if you're in a place with essentially no codes or zoning. My (fairly) newlywed and I built the house with basically no experience either.