A former teacher says he has been left "heartbroken" by the destruction of a historic school building that was once the home of pioneering pastoralist Sir Sidney Kidman, but has now been gutted by fire.
The former mansion at Kapunda in South Australia's lower north dates back to 1879, and was purchased about 20 years later by Kidman.
He named it "Eringa" after an outback station he owned, and it later became the "centrepiece" of Kapunda High School, where fire broke out last night.
Fire crews were called to the scene about 9:15pm and found the administration building alight.
Footage shows flames coming from the roof of the former villa.
"It was like a small, little fire and then it just gradually grew and got bigger, and then when it hit Eringa there were massive clouds of smoke and stuff, and then the roof caved in," one student said.
Kidman, known as the "Cattle King", donated the building — which suffered extensive damage in a fire in 1902 — to the education department in the 1920s.
"It was Kidman's former residence although he didn't build it, a guy prior to him built it and Kidman took it over from 1901 and then donated it, as a school, in 1921," retired teacher Paul McCarthy said.
Mr McCarthy, who worked there for 34 years, said he was "heartbroken, like everyone else".
"I invested a lot of time as a teacher and as a history teacher to understand the significance of the building in terms of local history, even state history or national history, given that Kidman was such a significant figure," he said.
"Every kid who's ever been here associates themselves with the building rather than the rest of the school."
Fire crews battled the blaze for most of the night and emergency services remain on the scene this morning to monitor conditions there.
Metropolitan Fire Service (MFS) commander Noel Dodd said the fire started in a nearby transportable classroom before spreading to the main building.
"[Firefighters] approached the fire to try and knock it out but were hampered by limited water supplies up here. This prevented the firefighters from attacking the [inside] of the demountable," he said.
"They were also hampered by a number of explosions from around the building."
It was then that embers spread to Eringa, leaving a damage bill "in the millions".
"My understanding is the main structural side of the building walls is still standing but there's been significant damage to the roof area," Mr Dodd said.
About 80 firefighters battled the blaze, which took three hours to control.
The cause of the fire is not yet known. Experts from Adelaide will visit the scene to investigate.
"It's still undetermined," Mr Dodd said.
"It's going to be hard to go through the debris but I'm pretty confident they'll find a cause."
In a statement posted to Facebook last night, school principal David Marino said there would be "considerable interruption to learning programs" today.
"We understand if you choose to keep your child home, while we are working through this incident and providing a modified learning program," he wrote.
"We will continue to keep you informed as we work through and rally our community."
The fire service said the blaze was contained but still producing smoke and residents had been advised to stay indoors with their windows and doors closed until the smoke passed.
Former staff member Anne Hornsey told ABC Radio Adelaide there was "heartbreak on everybody's face while they were watching this appalling thing happen".
"I can't speak for everybody but I know there would be a lot of people who have their heart in Kapunda High School and certainly there will be great support where it's able," she said.
Former alumni of the historic school include renowned author Colin Thiele, writer of the book Storm Boy.
"For there is no school in South Australia like Kapunda High School," he once wrote.
"In every way it is unique."
