Lawyers taken on by campaigners fighting closure of Stocksbridge Leisure Centre are applying for a court injunction to prevent the venue being closed.
Unity Law, which represents 4SLC, is asking a court to block closure of the centre by Sheffield Council and operator Sheffield International Venues, which is scheduled for May 1.
The legal action is taking place at the same time as ongoing negotiations between Sheffield Council and 4SLC about the campaigners and Stocksbridge Town Council taking over the centre.
Sheffield Council says it can no longer afford the current £400,000 annual subsidy - but campaigners believe they can run it more cheaply.
Chris Fry, managing partner at Unity Law, said: “Given the timescales involved, we have asked the court to consider the injunction application within the next 72 hours.
“The centre is due to close in two weeks, when the facilities and staff will be dispersed. This means that opportunity to reconsider the decision to remove the subsidy and close the facility will have been lost.”
Sheffield Council said it is willing to keep the centre mothballed until March so a viable rescue plan can be put together.
Coun Isobel Bowler, cabinet member for culture, sport and leisure, said: “We have always been and remain committed to working with 4SLC and others in the community to find an affordable and sustainable leisure offer in Stocksbridge.
“The legal processes, which appear to be being driven more by the lawyers than by the people of Stocksbridge, seem to me to be unnecessary and a distraction.
“If the council has to pay Unity’s fees this will come out of scarce resources - and we have no option but to defend the position on mothballing.
“We have been working with the 4SLC and the community since January and will continue to do so despite having to engage in litigation while also trying to work collaboratively. Ultimately we all want the same thing which is the continuation of leisure facilities in Stocksbridge.”