Government neglect and complacency in the wake of a previous tower block blaze could bear some of the blame for the Grenfell Tower inferno, experts have said.
And London mayor Sadiq Khan says "questions must be answered" about how the latest tragedy occurred.
Grenfell Tower in west London went up in flames early Wednesday morning, killing more than 12 residents in its 120 apartments on 24 floors and leaving scores more injured.
As the scale of the disaster sank in, fire safety experts and community leaders said lessons had not been learned from a similar, smaller fatal blaze in a tower block in south London in 2009 - despite a long and exhaustive coronial investigation.
Britain has 4000 tower blocks like Grenfell Tower that still lack fire sprinklers, against the recommendations of an all-party parliamentary group which has been pushing ministers for action since 2013.
Seperatetly, a blog written by the Grenfell Action Group, an organisation that advocated for residents of the property, in November last year said: "only a catastrophic event will expose the ineptitude and incompetence of our landlord."
"Unfortunately, the Grenfell Action Group have reached the conclusion that only an incident that results in serious loss of life of [the property management's] residents will allow the external scrutiny to occur that will shine a light on the practices that characterise the malign governance of this non-functioning organisation."
And in March this year fire experts warned that a government delay in reviewing building regulations could be endangering tower blocks throughout the UK.
One fire safety expert said non-fire resistant, even flammable materials were being used to make buildings more energy efficient.
In July 2009, three women and three young children died in a fire that spread through Lakanal House in Camberwell, south London.
An inquest into the deaths in 2013 found that a recent refurbishment adding 'composite panels' to the building "had a significant impact on the fire resistance of the external wall".
Coroner Frances Kirkham wrote to the government recommending a review of building regulations, "with particular regard to the spread of fire over the external envelope of the building", especially if renovations or refurbishments might reduce existing fire protection.
Newly-added aluminium cladding on Grenfell Tower has been blamed for helping the fire to quickly spread across the building.
The coroner in 2013 also said the government should encourage housing providers to retro-fit sprinkler systems in high-rise residential buildings.
And she said it should clarify the "stay put principle" under which residents are initially told to remain in their apartments if there is a fire outside.
Grenfell lacked a functioning sprinkler system, and residents who fled the building said they had been instructed to "stay put".
Southwark Council said after the 2013 inquest "we urge everyone in the country that has a responsibility in this area to ... try to ensure that nothing like this ever happens again and in order that those who tragically lost their lives did not do so in vain".
But Ronnie King, the secretary of the All-Party Parliamentary Group Fire Safety & Rescue Group, told LBC radio that the government had sat on the coronial report and not acted.
"Successive ministers since 2013 have said they are still looking at it," he said. "We've been waiting."
Those ministers include the previous Housing Minister Gavin Barwell, now prime minister Theresa May's new chief of staff.
Mr King said there were around 4000 tower blocks in Britain that still lack fire sprinklers.
He said in March that social landlords and housing providers could face multi-million pound legal costs and compensation should they experience a "Lakanal House tragedy".
Dr Jim Glocking, technical director of the industry Fire Protection Association, told the Guardian his organisation had "lobbied long and hard" for changes to building regulations, without success.
"Various ministers have said over the years that there will be an imminent review, but it keeps being put on hold, in spite of organisations like ourselves campaigning very hard," he said
Glocking said they had wanted rules to ensure that external insulation underneath cladding on tower blocks was fire resistant.
On Wednesday, a note on one of the earliest flowers placed at the scene read "Justice has to be done. People before money."
David Collins, of the Grenfell Tower residents association, told the BBC their concerns about the safety of the building had been ignored by the landlord and by the council.
They had complained about "fire safety concerns which were not investigated during the regeneration works", Mr Collins said. "(There were) concerns over locations of boilers, concerns about escape, concerns about fire escape lighting, the list goes on.
"I spoke to councillors and they refused to investigate."
Rydon, a company that recently finished a refurbishment of the building, said their work had "met all required building control, fire regulation and health and safety standards".
"We will cooperate with the relevant authorities and emergency services and fully support their inquiries into the causes of this fire at the appropriate time," they said in a statement.
Labour leader Jeremy Corbyn linked the fire on cuts to local government funding under the Conservative government.
"If you deny local authorities the funding they need then there is a price that's paid by the lack of safety facilities all over the country," he said.
He said it was too early to go more deeply into the question of blame, as the first priority was "saving life".
"Tomorrow is the day for searching questions, searching questions on the provision of fire safety equipment, the provision of sprinklers and the support the emergency services need and must have," he said
"The reports that have been made in the past have to be acted on and we will make sure they are."
Policing and fire minister Nick Hurd said checks would be carried out on other tower blocks going through similar refurbishment to Grenfell Tower.
A local builder called Alan told LBC radio he had been in the building many times and had noticed the stairwell doors were not properly sealed fire doors.
"There's a gap, that creates a draught which is the greatest thing for a fire, bringing oxygen," he said.
"And I said to them 'You've got so much plastic in this building, it's frightening'.
"I actually expressed my concerns about this at the time. It's the old story - lessons will be learnt. Well they're not."
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