The inside of the building has been exposed to the elements
The owner of Derby's Hippodrome theatre could be forced to pay up to £750,000 for repairs to the damaged building.
The Grade II listed venue suffered serious damage in March while undergoing repairs.
The city council is considering ordering Christopher Anthony to return the Hippodrome to the condition it was in before this damage was caused.
Mr Anthony has said he will appeal against any order, a process likely to last at least 12 months.
The building, which dates from the early 20th Century, had stood empty for some months before Mr Anthony was ordered to carried out urgent repairs.
During this work, much of the roof and large sections of external wall collapsed.
Now the council has said it will order Mr Anthony to repair the building or face an unlimited fine.
Repair work will cost a minimum of £700,000 and full restoration would cost millions.
The council, which is meeting on Thursday evening to discuss the matter, is also expected to go ahead with a separate prosecution over the damage.