About 30 firefighters were called out to tackle a severe blaze at a Shropshire school which badly damaged part of the building and led to hundreds of children being told to stay at home today.

Firefighters said only prompt action by crews stopped a large building on the campus of The Marches School, in Oswestry, being completely destroyed by the blaze, which broke out in a store cupboard.

The cupboard was destroyed and smoke caused severe damage to the school’s technology room.

An investigation has been launched into the cause of the fire, but school staff said that they understood it was not malicious.

Firefighters from Oswestry, Chirk, Ellesmere, Baschurch, Tweedale and Telford attended the fire at 6.45pm yesterday.

Adrian Bowen, from Oswestry Fire Station, said: “It was a severe fire. It took about 25 minutes for us to extinguish it. There was nobody in the building at the time.

“Thermal imaging cameras showed the heat was intense, about 100 degrees.

“If we had not got here when we did it would have been a lot more serious. If it had happened at 2am the whole building would not have been here in the morning.”

Headteacher Sarah Longville said children in years 7, 8 and 9 were being asked not to attend school today.

Tonight’s open evening at the school is going ahead as planned. And she said all pupils would be back in school tomorrow.