Emergency crews have tackled a fire at the derelict Fortfield Hotel near the seafront at Sidmouth in Devon.
Devon and Somerset Fire and Rescue Service said the alarm was raised at about 1620 GMT.
At its height, up to 80 firefighters were involved in bringing the blaze at the four-storey property under control.
Crews are remaining at the scene overnight to ensure hot spots do not reignite. It is not thought that anyone was in the building.
Police closed the seafront and water was pumped from the River Sid about a mile (1.6km) away to the scene.
Fire crews said they could only fight the fire, which started on the fourth floor, from outside the building because of safety concerns.
Adge Tilk, of the Devon and Somerset Fire Service, said: "It was so dangerous for us inside.
"The minute you walked in the door you found floorboards that were missing and there were voids. It was very, very difficult to work."
Hugh Johnson, duty manager of Dukes on the Esplanade in Sidmouth, said the roof of the Fortfield had fallen through the empty property and the flames "lit up the night sky".
"It used to be one of the most prestigious hotels in Sidmouth," he added.
The fire service worked to ensure sparks from the hotel did not spread the blaze to neighbouring properties.
Sidmouth Cricket Club, which is next to the hotel, recently had its roof rethatched at a cost of more than £40,000.
Club secretary Mike Dibble said: "There were sparks flying around, but mostly blowing the other way."
The fire was brought under control within two hours.
A small number of nearby houses were evacuated, but residents have been allowed to return.