A cost-cutting attitude among those working on the refurbishment of Grenfell Tower led to the disaster, Sam Stein QC, also representing bereaved and survivors, said.
He told the hearing: "It was the decision by Kensington and Chelsea the local authority, the TMO and its contractor to try to refurbish on the cheap that led to this devastation and this desire."
On the industry's persistence in using the type of material used on Grenfell Tower, he said: "Has this failure to deal with dangerous cladding something to do with serial incompetence or had industry become too close to government?
"Remember that the Celotex director Rob Warren made clear on the company website that they were working inside Government to influence policy and regulation industry."
A guide of how a fire could spread through Celotex material was removed from its website after the disaster last June, he said.