A Conservative council has defended its decision to allow development on gardens days before the government vowed to limit "garden grabbing".
Crawley Borough Council granted planning permission for social housing on two thirds of 21 gardens at West Way, Three Bridges, Sussex on 7 June.
Two days later communities minister Greg Clark outlined plans to stop developers building homes on gardens.
The council said the site was earmarked for potential development 30 years ago.
It also said it had 3,000 people on its housing waiting list.
Council tenants in West Way, who stand to lose about two-thirds of their existing gardens, said they received a letter telling them about the decision over the weekend.
Janet Ward said: "We're just devastated by it. We've been left with so little garden and the council just treated us with contempt. We're really upset."
Conservative MP for Crawley Henry Smith said he was opposed to the development.
He added: "Not only for the loss and the environmental impact of building on gardens but also for the impact on the local infrastructure, this is a decision I can't support."
When she was asked whether this policy went against the Conservative manifesto, Tory councillor Claire Denman said: "No, not at all because the bottom line is we didn't know that policy was going to be changed that quickly."
There is increasing concern among campaigners about homes being built on land attached to existing urban or suburban houses, which increases population density.
Last week Mr Clark announced plans to take gardens out from the brownfield planning category, used for ex-factory land, to stop "garden-grabbing".
He said it was "ridiculous" that vital green space was being lost.