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The problem is that building land is worth too much to private developers so they can rarely make the maths work.
I assume the difference between here and the Dutch system is that the Dutch system allows the local authority to buy land based upon its current usage, which in most cases I imagine would mean they don't have to pay for development value. Introduce that rule overnight in the UK and you'd have a lot of PropCos going bust overnight, which might not help the underlying problem.
Councils and other Registered Social Landlords [Housing Associations] can and do develop land for social housing in conjunction with private contractors.
The problem is that building land is worth too much to private developers so they can rarely make the maths work.
If local need can be proved, social housing can be built outside normal planning rules, for example on green belt land. This is working OK in certain parts of the countryside, where there is a lot of land which can be worth 10x or 20x more as social housing land than for agriculture, but not in cities and we mainly need houses in cities.