"Union lawyer Martin Seaward said there was a "near total failure" of fire safety measures at Grenfell Tower.
The June 2017 disaster at the west London tower block killed 72 people.
The comments came on the final day of closing statements in a section of the inquiry focusing on the fire safety measures in the building, its management, risk assessment and the communication with residents.
Mr Seaward criticised the approach to fire safety taken by the Kensington and Chelsea Tenant Management Organisation (KCTMO).
He told the inquiry on Tuesday the "hazardous rainscreen cladding system" should have been identified as a risk and removed by April 2016.
"Additionally, the near total failure of all the active and passive fire safety measures allowed the rapid deterioration of conditions inside the tower, which grossly impeded the firefighters' operations, including search and rescue," Mr Seaward said."
Maybe all the clever people should get off their arses and do something about it other than complain on DIY Internet forums from behind the safety of a PC screen?
Maybe all the clever people should get off their arses and do something about it other than complain on DIY Internet forums from behind the safety of a PC screen?