Berkhamsted Citizens Association (BCA) chairman Susan Johnson says the town’s planners copied her group’s objections to the design of a £2.3m school sports hall.
She spoke out after Berkhamsted Town Council’s planning committee ruled on Monday that plans for the development still included too much use of concrete.
Ashlyns School had already revised its plans to make the building smaller with more bricks where there had been concrete. But the authority again rejected the proposals.
Mrs Johnson said: “This was done at the BCA’s instigation, as before the council had only expressed concern.”
Ashlyns is Grade II-listed and in the Green Belt.