Campaigners are fighting to save a historic open-air swimming pool that has been closed for 30 years.
The baths could be replaced by a hotel and leisure complex
The King's Meadow baths in Reading, Berkshire, could be demolished as part of plans to develop the riverside site.
A petition containing more than 1,000 signatures has already been handed to Reading East MP Jane Griffiths who is to present it to the House of Commons.
Campaigners want the lido by the River Thames to be restored despite plans to build a hotel and leisure venue.
Campaigner Isobel Ballsdon told the BBC: "So much of Reading's old historical buildings are being destroyed and replaced with brash new buildings.
"This one is particularly sad to be at risk. It has been shut to the public for 30 years.
"I didn't know until a few weeks ago what was inside it and now that I do I am really very angry with the council that they have let a facility go unused for so long."
The lido has not been in use for the past 30 years
Public consultation on plans for the site are currently ongoing and campaigners are to raise the issue at a meeting of the council on Tuesday.
A spokeswoman for Reading Borough Council said that no detailed plans for the site had yet been drawn up.
She said: "Both the Environment Agency and Reading Borough Council are looking to improve recreational and riverside facilities for local people and visitors.
"Any application made at this site will be subject to planning procedure.
"The future of the site will be an item on the agenda at Reading Borough Council's culture scrutiny panel meeting in October where full and open debate will be held upon all of the relevant issues."