The fire in a mobile classroom at Nunthorpe School is believed to have started on Sunday night.

Residents living near the school are being asked to report if they saw anything suspicious.

Headteacher, Jon Rowling, said he was disappointed that such an attack could happen in Nunthorpe.

He said: "You think anything could happen anywhere so we don't think we are beyond that possibility, but you always hope it won't.

"You hope that people have got more sense, but unfortunately, there are some very silly people and sometimes some very wicked people.

"Which of those it is in this instance, I don't know, maybe we will find out one day.

"It is certainly utterly irresponsible and it causes nothing but inconvenience."