A pressure group has urged its council to reconsider agreeing plans for hundreds of new homes, and to "work in the interests of its residents".
West Norfolk Council submitted plans for 379 new homes on 48 acres off Gaywood Parkway in King's Lynn, which included a new bridge across the sand line which serves the quarries at Leziate.
More than 3,500 people signed a petition opposing the development, including Stephen Fry, and 237 objected on the council's planning website.
Last week, councillors gave the development the go-ahead.
Following the decision, King's Lynn Civic Society called on councillors to question whether they had a "clear vision" for King's Lynn and if they felt they were working in the best interests of residents.
In an open letter, its chairman Alison Gifford said: "It cannot be right that the council finds itself as landowner, developer and planning authority giving itself consent for a scheme, partly on unallocated land, and at the expense of a large area of green infrastructure within the town, when thousands of residents have registered their objections.
"It seems completely implausible that a private developer would have been granted this consent."
The society accused the council of making a "political decision" to adopt ‘growth point status’ and expand King’s Lynn.
The chairman said: "Traffic congestion continues to get worse in the town. Whilst we keep losing our public green spaces, trees and other informal landscape features, we are still unaware of any strategic plan to replace them."
In last week's meeting, committee chair Chris Crofts said the link road and bridge would improve traffic issues in the area and ease pressure on roads.
He added that elements of the development outweighed any possible harm.
The Civic Society also argued it would be possible to build around 200 houses at the western end of the site and "still improve and expand public open space" and enhance public transport access for the town.
The chairman said: "We hope it is not too late to ask for this planning decision to be reconsidered and that councillors put the wishes of residents before loyalty to any particular political group."
West Norfolk Council declined to comment.
A ’super group’ is also being formed to fight the decision.
Members of groups including Nature Volunteer Network (NVN) , King’s Lynn Klimate Concern, Friends of the Earth Fenland and West Norfolk and Extinction Rebellion King’s Lynn and West Norfolk are said to be onboard with the campaign to continue fighting against the scheme, as well as a "plethora of concerned citizens".
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