Breeze blocks fell through the roof of a classroom, and sent two children to hospital.
The five-year-olds, pupils of Oatlands School, St Mary's Road, Weybridge, suffered minor injuries after the blocks came through the ceiling.
They were hit by the blocks during a lesson at about 1.30pm today.
Police, paramedics and firefighters were called after receiving reports that at least five breeze blocks had fallen, and struck some children.
Following the incident, it was reported that all the pupils were led from the school.
Two children were treated before being taken to St Peter's Hospital with minor injuries.
There were reports of a black tarpaulin covering the part of the roof where tiles were missing, as scenes of crime officers inspected the classroom.
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