Grenfell Tower was not fit for people to live in, a senior London fire brigade officer has told the public inquiry into the disaster that claimed 72 lives.

Its deputy assistant commissioner, Andrew O’Loughlin, the most senior officer present when the advice for residents to stay put was changed to evacuate, said the building should have protected people who were staying where they were and he could not understand why the advice had been changed.

Speaking during the final week of evidence from firefighters who attended the blaze on 14 June 2017 he said: “The building was so horrendous several hours later that I think no one should have lived in the building.”

He continued: “So to say we should have changed the ‘stay-put’ advice, I don’t think would have been reasonable based on something that happened several hours later that none of us could ever have expected.”

His evidence cast fresh light on the confusion among firefighters as the 24-storey tower was engulfed in flames fuelled by combustible cladding and a litany of faults including failed fire doors, broken smoke ventilation systems and a fire lift that could not be properly commandeered. The inquiry has already heard that the stay-put policy had effectively failed at 1.24am and was only changed at 2.47am.

Some 25 minutes passed before O’Loughlin was informed of the change, the inquiry heard. He also received no updates from the unit coordinating calls from trapped residents during this time who were being given fire survival guidance by phone operators.

O’Loughlin told the inquiry he was “confused” by the change in policy and did not think it would necessarily make a material difference to the rescue plan.

“You wouldn’t expect fire to spread around the building like it did on the outside, and for it to fail so catastrophically, we’d never expected or anticipated that would do that in the way it did, and then similarly … we would not expect the internal protection to fail so badly as well,” he said. “So my expectation was people who were safe in their flats should stay safe in their flats.”

The counsel to the inquiry, Richard Millett, pressed him, asking: “On what you later discovered during the course of the night, do you accept that the revocation of the ‘stay-put’ advice should have happened at an earlier stage than it did?”

O’Loughlin answered: “I don’t think you could say that a decision could be taken earlier based on what I saw several hours later.”

The inquiry is currently in its first phase of evidence at Holborn Bars, central London, focusing on the events of the night of the fire. A second phase, not expected to start until next spring, will examine the decisions involved in the refurbishment of the council block which was owned by the Royal Borough of Kensington and Chelsea.

On Thursday, the LFB commissioner, Dany Cotton, is expected to give evidence. The bereaved, survivors and residents are scheduled to begin their evidence next week amid continuing concern about the location of the inquiry, seven miles from Grenfell.

The inquiry is intending to release an interim report in the new year which is likely to make recommendations about the safety of cladding systems similar to those used on Grenfell which contributed to the spread of the flames.