A fire investigation is to take place into the fire at Blatchington Mill School.
East Sussex Fire and Rescue Service was called at 5.42pm on 17 January 2024 to the property in Hove.
There are no reports of injuries and everyone was quickly accounted for.
Crews used breathing apparatus and hose reel jets as well as thermal imaging cameras.
At its height, six fire engines were on scene, as well as officers and other agencies.
One fire engine remained at the scene overnight, checking for hotspots.
As of 6.30am on 18 January 2024, we have left the area.
We will return to assess damage and carry out a fire investigation.
No further details are being released at this stage.
We would like to thank nearby residents for their patience during the operation last night.