Bosses running The Leadmill live music venue and nightclub have demanded Sheffield City Council leader, Tom Hunt, back their campaign to "save" it.
They operate from Leadmill Road but do not own the live music venue, which was bought in 2016 by The Electric Group, who now want to fully take over the building.
A spokesperson for The Leadmill said: "Tom, of all people, should know that this hostile takeover risks fundamentally and forever changing the course of our city, heritage, and culture. It may start with us at The Leadmill, but it goes much further than that.
"If we don’t stop this hostile takeover, the very soul and character of our great city is at risk. Tom needs to pick a side."
Leadmill bosses are asking locals to exert pressure on Mr Hunt, urging him to publically back the current team at the live music venue.
The spokesperson said: "That’s why we’re asking you – the great people of Sheffield (and further afield!) to help us win this battle. It’s simple, easy and quick: we need you to #TellTom to back our campaign.
"We need you to #TellTom how you feel about this hostile takeover and #TellTom to join us in this Battle for the Soul of Sheffield. You can #TellTom by email, letter or tweet him."
Bosses at The Electric Group, who bought The Leadmill building in 2016, have insisted their vision for the future is "all about continuity of programming".
In 2022, the firm issued an eviction order for the current tenants, but The Electric Group co-founder Dominic Madden said his company "cherish" the venue's legacy and are hoping to preserve it - contrary to the belief of current operator, Phil Mills.
Speaking earlier this year, Mr Madden told The Star's Kirsty Hamilton: "Mills is very upset because he has profitable businesses coming to an end, and he's just trying to cause as much difficulty as possible. He's trying to present me as a mainstream nightclub operator, who doesn't understand the cultural significance of The Leadmill."
Since taking over as the leader of Sheffield City Council in May, Mr Hunt hasn't taken a position over the Leadmill debate, which the current operators would like him to do.
Addressing the Sheffield public, a spokesperson for The Leadmill said: "We have been overwhelmed by your support so far, but we can only win this Battle for the Soul of Sheffield with your help, so let’s get out there and #TellTom how we feel.”
The Electric Group has filed a legal case to have Mr Mills and his management team removed from the building. They hope it will be heard in the first quarter of 2024, meaning the firm could be in control of the venue within a year.