More than two years after the Grenfell Tower disaster, the London fire commissioner has indicated that firefighters still need guidance on what to do if a building is burning out of control and advice to “stay put” is no longer safe.

Delivering an interim report into how the London fire brigade (LFB) has responded since the 14 June 2017 tragedy claimed 72 lives, Dany Cotton said on Wednesday that a review of stay put policies was needed, admitting “considerable challenges” remained in moving away from the policy that is widely believed to have cost many lives at Grenfell.

“Buildings designed to have a stay put strategy, which includes Grenfell Tower, are not designed and built to facilitate mass emergency evacuation during a fire – many, for example, have a narrow staircase and no common alarm system,” Cotton said. “New research is now needed into what the public and firefighters should do when a building fails.”

Speaking to London assembly members 10 days before the Grenfell Tower public inquiry is due to issue a report expected to be critical of the fire brigade, Cotton maintained the LFB’s defence against allegations its failures may have cost lives. “The brigade itself was let down by decades of neglect of fire safety,” she said.

“London fire brigade aren’t the solution to this problem,” she said. “The solution is for buildings to be built, managed and inspected properly.”

However, the LFB’s first public progress report about lessons learned since Grenfell revealed the fire brigade still has not assessed the fire risk of all 6,900 residential high-rise buildings in London.

Cotton told the London assembly it had not conducted any evacuation drills on residential buildings that normally have a stay put policy in the event of a fire. Two hundred and 16 buildings in London have had their stay put procedure cancelled and replaced with evacuation plans.

The report also conceded the brigade had not properly gathered data about Grenfell Tower and that important information was missing or inaccurate. Electronic plans of the buildings, showing information to help crews find lifts and water mains, were not filled out properly.

On the night of the fire, there was little evidence of key decisions being recorded, the report concluded, even though this was “crucial” to enable proper command of the incident. Officers struggled to identify who was being evacuated, which potentially led to some flats still containing residents not being searched. Refresher training had not been provided to 999 phone operators tasked with giving survival guidance to residents.

When Cotton gave evidence to the public inquiry into the disaster, she was widely criticised for claiming that to prepare for a fire like that at Grenfell would have been akin to preparing for “the space shuttle landing on the Shard”.

Dany Cotton, the London fire brigade commissioner. Photograph: Yui Mok/PA

She reiterated that position, telling the London assembly that “no cladding on a building should behave in that manner” and that cladding fires had not previously spread inside buildings.

However, the inquiry was previously shown a 2016 LFB document that detailed the risk that cladding fires could break through windows.

Survivors and the bereaved fear Cotton is seeking to deflect responsibility from the LFB actions on the night of the disaster ahead of the report.

Cotton said on Wednesday: “I want the public and especially the Grenfell Tower community to know everything we are doing to learn from that night and to prevent a tragedy like this from ever happening again.

“Fire spread the entire height of Grenfell Tower in less than 30 minutes,. Residents and firefighters were placed in impossible conditions we had never experienced before. That is why I am calling for the government to reverse more than 20 years of neglect in relation to fire safety and to undertake urgent research on ‘buildings that fail’, which means stay put advice is no longer viable in those buildings.

“Since 2014, there have been more than 5,000 high-rise fires in London alone and in the vast majority of these incidents stay put advice has been effective. It’s very important for people to know that. It is completely understandable that stay put advice has been questioned, but we are talking about buildings that fail, rather than advice that fails and there is no clear alternative, which is why this research is needed.”