“We share the frustration that many will feel that the exact cause of the fire has not been identified,” Penny Macbeth, director of the art school, and Kristen Bennie, interim chairman of the board of governors, said in a statement.

They added that they were committed to a “faithful restoration” of the building, which they hope can open between 2027 and 2032.

Ross Haggart, deputy chief officer at the Scottish Fire and Rescue Service, said the investigation had been “a deeply complex and protracted process”.

“We scrutinised every aspect of this fire to ensure our investigation was as robust and thorough as possible,” he added.

“Unfortunately, almost everything within the building was severely damaged or consumed in the fire and that included any potential items of evidence that could have provided answers.”