A former soldier has started a campaign to save an old Royal Navy swimming pool described as "an architectural gem".
HMS Ganges in Shotley Gate, Suffolk, was a training centre for recruits between 1905 and 1976.
Plans are approved to build 280 homes there, but campaigners said there was "an understanding" the pool building would be renovated, not demolished.
Developer Galliard Homes declined to comment, but Shotley Parish Council said it was "not financially viable".
Colin Darroch, a local resident and ex-Army officer, said the building had "an elegant flowing symmetry to the design... best be described as an architectural gem".
"It is a fabulous building with the potential to be a truly outstanding facility," he said.
"There has long been an understanding and expectation the pool would be retained and restored."
Within days of it going online, nearly 1,000 people had signed Mr Darroch's petition calling for it to be saved.
Shotley Parish Council said the pool had reached "a non-financially viable state of disrepair".
A spokeswoman said: "The council contacted the developer two months ago to find out whether the demolition process could be halted to allow time for a community group to be formed and look at whether the pool could be saved.
"The response included an assurance that the demolition process would go ahead, but that an alternative site may be provided for a new, smaller pool."
Planning permission for the 280 homes was granted in 2015 by Babergh District Council, but construction has yet to start.
A Babergh spokeswoman said: "We are not aware of any feasible business plan to indicate the building is capable of being restored and operated on a viable basis.
"The pool is not a listed building, and the owner is within their right to take this action."