An application to have Belle Vue House listed has been made to Historic England.
Planning consultants FullerLong have submitted the application, with campaigners hoping this will protect the building at least after a buyer, believed to be hotel chain Premier Inn, was found for the site which includes the former outdoor swimming pool.
Theo Bird, who organised the application and had attempted to buy the site as part of the The Sudbury Community Estate Bid, said: “The process will take a few months before we know the outcome, but time is on our side as the purported purchaser has yet to submit a planning application.
“The community whip round would like to thank all those who contributed to raise the money in under 24 hours.”
He added that if the buyer pulled out, the Community Bid would still be happy to look again at a scheme, particularly with the Hardwicke House Group Practice, which is needing to relocate.
Mr Bird said he felt the surgery had been let down.
Sudbury town councillor Ellen Murphy added: “I am of the view that Belle Vue House and grounds are a vital part of Sudbury.
“To even consider demolishing such an iconic building is totally unacceptable. The argument for saving Belle Vue House is also an argument to keep all of Belle Vue Park.
“Babergh District Council do not own Belle Vue, they are merely caretakers on behalf of the community of council tax payers.
“We, as a town council, should protect, respect and preserve Belle Vue for future generations and use it as a hub for residents.
“Too many English historical buildings were destroyed in the late 1960s and into the 1970 and 1980s, with a detrimental effect on town and village life.
“Now is the time to stop, think and defend Sudbury. The majority of residents are appalled at such wanton destruction.”