THE discovery of asbestos in the Mackintosh Building of Glasgow School of Art led to a delay in installing a fire suppression system.

The system was not in place at the time of the disastrous fire in May.

The delay formed part of a series of events that led to the blaze which destroyed the Mackintosh Library and much of the west end of the historic building.

School director Professor Tom Inns also revealed that students had been told not to use expanding foam dispensed from canisters - the substance which was set alight by electrics within a film projector, leading to the blaze.

Professor Inns, who said no one was being disciplined for the incident, said: "That is not something that should happen. It was an accident and an error of judgment."

The official Scottish Fire and Rescue Service investigation report confirms that the suppression system was not fully installed at the building and was not operational on the day of the blaze in May.

It also revealed that one unnamed person was assembling work made from foam panels with one wall left blank to receive images from a projector.

The person was filling in gaps between the foam panels by applying foam directly from a canister when the flammable gases in the tin were sprayed close to the projector and drawn into its cooling fan.

The projector ignited the gases with its electrical components, burned through the plastic of the projector and then lit the foam walls behind it.

The report found that the fire's rapid progress through the Charles Rennie Mackintosh designed-building was aided by timber-lined walls and voids, and ventilation ducts running both vertically and horizontally throughout the building.

It says "a fire suppression system, designed to enhance existing fire protection measures, was being installed and was in the latter stages of completion; at the time of the fire the system it was not fully commissioned and was not operational."

The Glasgow School of Art has commissioned an external review of its management of the critical incident.