One of the many questions those involved in the blighted refurbishment of the "Mack" – the destroyed Glasgow School of Art building – are refusing to answer is why a cheaper and flammable insulation was used and not one which would not burn. From their silence we may draw our own conclusions.

The GSA trustees and director have placed their own brand of omerta, the mafia code of silence, on everyone and anyone who had the slightest involvement or knowledge of the the fire which destroyed Glasgow's precious jewel. This was not a privately-owned building with commercial secrets or data to protect. It was paid for by all of us, as are the director and staff. With their refusal to answer they display a breathtaking contempt, not just for the media, but the general public in what was – for the second time – a preventable disaster.

There is no rush to judgment over the cause of the fire, it is proper that the investigating authorities are given time to discover it, as they will do. But enforced silence must not be allowed to protect those who should be taking responsibility and have manifestly failed to do so. After an initial burst of concern politicians have also appeared to slump into an unspoken agreement that the same people who were not held to account in the 2014 fire can escape once more. There must be a thorough-going inquiry, led from Holyrood, into one of the great and avoidable tragedies of our times.