A blaze which caused severe damage to part of an Oswestry school was an accident and was probably caused by a laser cutting machine, fire experts said today.

The fire at The Marches School on Wednesday evening led to hundreds of children being told to stay at home yesterday.

Almost 30 firefighters were called out to tackle the blaze which destroyed a store cupboard and caused smoke damage to the school’s technology room.

Fire investigator John Griffiths said he visited the school yesterday morning to ascertain the cause of the blaze.

He said: “The fire was accidental and involved a laser cutting machine. Either there was an electrical fault with the machine itself or there was an ignition of materials that were being cut and had smouldered.

“The caretaker staff who found the fire did a good job and their actions helped confine the fire.

“They made sure all the doors were closed in the building where the fire broke out and they called the fire service promptly.

“Crews faced a severe fire when they arrived and did a good job in tackling it.”

He added: “It is not unreasonable to say that if people had not been on site when the fire broke out the damage would have been more serious. Most of the building where the fire was would potentially have been destroyed.”

The fire led to children in Years 7, 8 and 9 being told not to attend school yesterday. Children in Years 10 and 11 attended as normal.

School business manager Sarah Davies said all children were expected to attend classes today.

She said: “Work is being carried out on the building which was damaged.

“It is difficult to say yet what facilities will be available in that part of the building in terms of IT but classes will be held. Only one teaching room was badly affected by smoke.”

She added: “The school would like to thank all the emergency services for how promptly and efficiently they dealt with the fire.”

Headteacher Sarah Longville paid tribute to the school staff who helped in the aftermath of the fire, and particularly caretaker Ken Morris.

She said: “I would like to thank our caretaker Ken Morris who saw the fire and tried to extinguish it himself before calling the emergency services.

“Lots of staff came in as soon as they heard about the fire on Wednesday evening and I have been overwhelmed by their support.”