Crews used 10 breathing apparatus, two hose reels, two jets, two compressed air foam jets and the aerial ladder platform to bring the fire at Winton School in Andover under control.
Group Manager Dan Tasker said: "The first crews to arrive were met with a challenging situation of a confirmed fire plus the evacuation of 500 pupils."
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Kent Police have released an e-fit image of a man they are trying to trace following an attempted robbery and sexual assault.
Tuesday afternoon's forecast for the east of the region
Tuesday afternoon's forecast for the west of the region