THE owner of one of the county's most important landmarks has put in temporary measures to save the building from ruin.
But the move at Belper North Mill was not enough, according to a borough councillor and chairman of the mill's board of trustees.
English Heritage previously expressed concern over the grade one listed mill because of the state of the building's roof.
Amber Valley Borough Council and English Heritage contacted the building's owner, First Investments, to express concern over the damage a leaking roof could do to the integrity of the building.
This came a year after First Investments was forced by a court order from English Heritage to make improvements to the roof.
Peter Arnold, ward councillor for Belper South and chairman of the North Mill board of trustees, said that the latest temporary measures were not satisfactory.
He said: "The roof needs completely renovating. If it's left much longer it will become damp and affect the internal structure of the building.
"Around five years ago, Amber Valley Borough Council wanted to put an enforcement order on the building but didn't have the resources to do so.
"This would have meant the council would have carried out the works and the owner would foot the bill but it is taxpayers' money and the council could not afford it when it is close to £1 million."
Mr Arnold said that, if the mill fell into ruin, it would not just be a loss for Belper or Derbyshire but for the world.
Dr Anthony Streeten, planning and conservation director for English Heritage in the East Midlands, said: "The North Mill at Belper is on the heritage at risk register and we are worried about the future of the building.
"In response to the concerns of both Amber Valley Borough Council and English Heritage, the owner has carried out short-term measures to seal the leaking roof.
"The continued effectiveness of these temporary repairs is being monitored by the local authority."
First Investments was unavailable for comment.
