As the inquiry into the 2017 disaster breaks for a recess, what are the key facts from the evidence heard so far?

It took 36 minutes for a fourth-floor kitchen fire to sweep 20 storeys up to the top of Grenfell Tower in the early hours of 14 June 2017. The public inquiry into the disaster, which went on to claim 72 lives, is taking far longer. Barristers are now homing in on what happened second by second, with much of the evidence centring on the controversial refurbishment of the 1974 building, ordered in 2012 and completed in 2016.

Serious fire safety breaches

The inquiry has heard from several witnesses that Grenfell Tower was riddled with faults that accelerated the fire and made survival harder. Dr Barbara Lane, a technical expert, said a “culture of non-compliance” had meant more than 100 fire doors failed fire regulations.

The mechanical smoke ventilation system broke eight days before the fire, according to Martin Booth, the managing director of PSB, which made the system. No one involved in the refurbishment, or in the council’s building control department, seems to have checked on how the external cladding system (installed as part of the refurbishment) performed in a fire.

‘A merry-go-round of buck-passing’

Counsel to the inquiry Richard Millett QC warned organisations involved in the refurbishment evidence not to “indulge in a merry-go-round of buck-passing”.

Celotex, which made the combustible insulation, said little beyond issuing condolences. Arconic said that while the core material in the cladding panels it supplied was “obviously combustible”, they were “at most a contributing factor” to the fire.

Professor Luke Bisby, a consultant to the inquiry, had said they were the primary cause of fire spread across the building. Arconic claimed no one would have died if the uPVC windows had been built with greater fire protection. It was also up to purchasers to decide if its panels could be “safely and appropriately used”, it added.

London fire brigade and cladding fires

An internal LFB document issued in 2016 showed pictures of raging cladding fires in Dubai, Shanghai, Grozny and Baku. It concluded: “There is a need to understand what products are being used in the facade system and their fire behaviour”. The LFB also sent a letter to some London councils warning “external fire spread on high-rise residential buildings as a result of being clad in combustible panels presented a generic health and safety issue”.

Yet its firefighters knew very little. Michael Dowden, the first incident commander, agreed his knowledge of this risk was “as good as the person in the street”.

The ‘stay put’ strategy

The fire spread so fast that the official “stay put” strategy (advising residents to stay in their flats rather than enter potentially hazardous communal areas) failed at 1.23am, according to Dr Barbara Lane, one of the inquiry’s fire safety experts. Yet the London fire brigade kept the policy in place until 2.37am, when 107 people were still inside. Only 36 got out.

The LFB asked if evacuation was feasible with only one staircase, no fire alarm and no way to communicate an evacuation alert.

Dowden said he had not been trained in how to reverse “stay put” and did not have enough resources to get people out. More senior officers arriving around 45 minutes before “stay put” was abandoned thought an evacuation should have been ordered.

Firefighters were sent in to evacuate some people while 999 operators were telling others to stay put. Sharon Darby, an operator 13 miles away in east London, said she had no idea how bad the fire was. “I remember googling the fire and thought to myself, ‘oh my God, we’ve been telling people to stay put (in) that’.”

Facebook Twitter Pinterest Grenfell Tower in June this year. Faults in the building made the fire harder to control, the inquiry has been told. Photograph: Rick Findler/PA

Firefighters went into ‘a war zone’...

One of the first firefighters into the building, Charles Batterbee, described the scene as “a war zone”.

After just 20 minutes, Dowden was outside his comfort zone. As a watch manager, he should have been in charge of a fire requiring only four pumps. By the time he was relieved, it was a 25-pump fire. He was “consumed by sensory overload”.

Firefighters found the building only had a dry riser, rather than a wet riser, which is mandatory for buildings more than 50 metres high. This meant high-pressure water could not get to the top of the building.

A routine fire brigade document supposed to contain building details had not been updated since 2009.

... but showed remarkable bravery amid panic and terror

“I have never seen fear in the faces of the firefighters as I saw that night,” said firefighter Daniel Brown. But one by one they risked their lives.

David Badillo and Chris Secrett climbed 20 storeys to try – in vain – to rescue Jessica Urbano Ramirez, 12. She had moved up to the 23rd floor, but they did not know because radio communications had “completely failed”. Secrett almost ran out of air and put himself in a corner of the stairs to be out of the way if he died.

The evacuation

Failing radios meant information from 999 calls was ferried into the building on pieces of paper, the inquiry heard. For a period there were not enough firefighters in breathing apparatus to try to rescue people. Some gave their respirators to children, which meant they themselves inhaled toxic smoke.

One firefighter carried an unconscious child and couldn’t tell if they were dead or alive. Many firefighters later required medical attention.

Two firefighters who went to the 16th floor to save a man and came back down with Ed Daffarn did not realise they had actually been sent to rescue bed-bound Joseph Daniels, 69. They had knocked on his door but there was no answer. Daniels died.

Living with trauma

During the hearings, hardened firefighters needed regular breaks. They rarely shed tears but their faces would sometimes go blank as if some overwhelming thought or feeling had overtaken them.

Gareth Cook, who ferried child casualties, described how his trauma was triggered at a friend’s barbecue. Glyn Williams, who co-ordinated the 999 information at the base of the tower, said the fire had had “a massive emotional impact”.

“I have found it very difficult to deal with the events of Grenfell Tower,” Dowden told the inquiry.