Campaigners are calling on Sheffield Council to rethink the demolition of Castlegate Tower at the former Castle Market.
Twentieth Century Society Yorkshire says the eight-storey tower on Waingate should be preserved when the market is knocked down and used as part of the regeneration of the area.
Campaigners say they support the plan to expose castle ruins and create an urban park but the 1960s tower should be retained because of its ‘architectural merit’.
They believe it could be re-used as offices or as a viewing platform.
Emma England, an architectural historian involved with the campaign, said: “It’s the greener, cheaper, more sustainable option.”
The council said the tower forms an integral part of the market that would be ‘difficult to isolate’ and make secure at ground and first floor levels without ‘significant extra costs’.