Lanner Parish Council, which had argued that the scheme on the outskirts of the village broke housing and countryside protection policies, last week lost its action against Cornwall Council's decision.
It has already applied to seek leave to appeal but has yet to decide whether to pursue the case further in the courts.
In the meantime, Councillor Mark Kaczmarek, who lives in the village and is Cornwall Council's cabinet member for housing and planning, has written a bruising letter to the parish council accusing it of wasting tens of thousands of pounds.
Coun Kaczmarek wrote: "What can not be overlooked and what is inexcusable is that the actions of the parish council have cost Coastline Housing well in excess of £200,000, cost the public sector a significant amount of money, risked the loss of around £3 million in funding that Coastline are reliant upon to undertake the development and delayed the provision of much needed affordable housing within the parish.
"This is in addition to the reputation damage that the parish council has caused to itself and those putting their faith in local democracy and the will of Cornwall Council to facilitate the provision of affordable housing where it is right and proper to do so."
He also accused the parish of being "ignorant" or having "disregarded" the duty of Cornwall Council to provide housing and denied people new affordable homes.
He added: "The financial and emotional cost to those people is unimaginable and your parish council has let down the very people it should have been supporting."
In his four-page letter, Coun Kaczmarek also accused the council of wasting £20,000 on the "unpalatable episode".
He went on: "I will leave it to the conscience of every parish councillor as to whether they contribute personally to the wasted costs."
The legal challenge by the parish council, which had argued that under local policy only "about 12" affordable homes would be allowed on an "exceptional" rural site, was rejected by the High Court a week ago.
Judge Anthony Thornton QC ruled the limit on the number of homes was not set in stone.
Ashley Wood, chairman of the parish council, said his initial reaction to the letter was "unprintable".
He declined to comment further until the letter had been discussed by the full council. It meets on Thursday when it is set to decide whether to take the matter to appeal.
Mr Wood has already said that was "likely".
He said when the judge's decision was made: "The decision appears to fly in the face of the principles underpinning the much-trumpeted localism.
"For instance, where previously local need was intended to be established at parish level, there is now the real possibility that Cornwall Council will assess this on a district or even county-wide level.
"The effect of this is that village communities across the county could face development on a scale that far exceeds the needs of their particular villages."