Firebugs are thought to be responsible for starting a blaze which wrecked part of a primary school.
A section of St Mark’s Primary, in Barrhead, went up in smoke last night, sending black billows across the skyline.
People came out into the streets surrounding the Roebank Drive primary as fire teams arrived.
Now police are trying to find out if youths were responsible for the incident.
Three fire crews spent two-and-a-half hours battling the blaze.
Barrhead Police Inspector Michelle Grant said : “We received a call around 9.30pm following reports of a fire at St Mark’s Primary in Roebank Drive.
“Emergency services attended and the fire was extinguished but the building suffered extensive damage.
“We are carrying out enquiries in effort to establish who was responsible.
“If anyone has any information, I would ask that they contact Police Scotland on 101, quoting 3858 on 25 July, 2021.”
East Renfrewshire Council will also carry out an investigation to see if the blaze will impact on the 350 pupils returning on August 16.
A spokesman for the Scottish Fire and Rescue Service said: “We were in attendance last night at a fire at a school in Roebank Drive, Barrhead.
“We got a call at around 8.53pm about a fire at the school in itself.
“Three engines attended. We left at 11.35pm. There were no casualties.”
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In recent months the town has been hit by a surge in fire-raising, including at a stables and at Fereneze Golf Club.
On social media one local said: “Shocking and probably little neds viewing from a distance too.
“This is tragic and affects all the pupils as won’t be there for start of new term.”

An East Renfrewshire Council spokesman said: “Following the fire at St Mark’s Primary on Sunday night our staff will assess the damage, alongside colleagues from Scottish Fire and Rescue, and the required repair works will be carried out as quickly as possible.
"We await further updates from police and fire colleagues about the cause of the fire.”