A TEA light candle placed under a plastic play house caused the fire which devastated a infant school, believe fire service forensics officers.

Matt Jones, station manager for the Fire Crime and Investigation Unit at South Wales Fire Service says: "Following investigation at Thornwell primary school, we've based our findings on the evidence recovered by myself and the CSI and comparing this to witness statements from the original caller and the first attending crews.

"It is my opinion that the fire was caused by a person or persons unknown leaving a tea light candle burning in the pvc construction play house.

"The play house was placed directly against the building allowing the flames to penetrate the wooden construction of the school. The fire would have also spread rapidly throughout the school due to the open common roof space".

A Gwent Police spokesman added: "Our investigations are still ongoing. Although there's no evidence to suggest deliberate ignition, due to the recklessness of the act we're investigating it as arson.

"In particular we're trying to trace a male in a grey hooded top who was seen running from the school towards the Bluebell Drive area at the time of the incident.

"We would encourage anyone with information to call Gwent Police on 101 or Crimestoppers anonymously on 0800 555111."

•For the full story on how Thornwell Primary school is bouncing back and looking to the future, see centre pages.