Firefighters worked to extinguish a blaze at a secondary school in Somerset.
Five crews were called to Writhlington School, near Radstock, at about 1430 BST on Thursday.
An Avon Fire and Rescue Service spokeswoman said the assembly hall was ablaze but it was not yet known how the fire had started.
The building was evacuated and all 1,450 students at the school were accounted for, the spokeswoman added.
Parents were informed by text message that there had been a fire and everyone was safe.
Avon Fire and Rescue Service spokeswoman Stephanie Mounsey said: "The firefighters will continue to work to cut away the roof space to ensure all the fire hotspots are fully out.
"Once that's done, an investigation into the cause of the fire will begin."
Some £25m was spent on new buildings at the school last year but the fire happened in the old part of the site.
The school is due to open as normal on Friday.