Residents of the 40-year-old apartment building in north Kensington claimed that the fire alarms were not working, giving them no warning of the blaze that spread from the second floor to the 27th.
The fire is thought to have started because of a faulty refrigerator on the 3rd or 4th floor of the building soon after midnight and destroyed flat after flat.
At least 45 fire engines and over 200 firefighters and officers have been deployed to the scene, the London Fire Brigade said. "In my 29 years of career as a firefighter, I have never ever seen anything of this scale". "Sadly, I don't anticipate there will be further survivors", he said.
The death toll has already doubled in the last few hours and the news is predicted to become more gloomy in the hours ahead.
"It is too early to speculate what caused the fire and contributed to its spread".
Another said how they'd seen a baby thrown from an upper floor and caught by a bystander.
Residents who escaped told how they woke up to the smell of burning and rushed to leave through smoke-filled corridors and stairwells.
At Portobello Rugby Club, Kayo Mneimneh, 31, and Hassan Filali, 26, described watching the tragedy unfold and how the fire suddenly flared up to engulf floors where people were trapped. The most important factor is ensuring the safety of those who were trapped, ensuring they are receiving the best medical treatment and also putting measures in place to ensure people have somewhere to stay at this incredibly hard time. Critics have suggested it should not be relying on public donations to help tenants who have lost homes and belongings and, in some cases, family and friends.
One witness said she heard people screaming and could see residents flashing their phone lights inside the building.
"The fast saved a lot of people, as they were... up preparing to eat before sunrise", he said. It was fire up, up, up.
The disaster occurred 10 days after a terror attack at London's Borough Market, and some locals said they initially feared the fire was also terror-related, though authorities discounted that possibility.
London Fire Brigade officials have been able to search most of the building and firefighters are now on the top floor of the 24-storey building.
"We've complained to council, " said Edward Daffarn, 55, who said nothing had been done to improve safety.
"I'm lucky to be alive".
The British company that carried out the tower's 2016 refurbishment, Rydon, said in a statement that its work "met all required building control, fire regulation and health and safety standards". "I consider this mass murder", he said of the blaze.
The 1974 building was refurbished recently at a cost of £8.6 million, with work completed in May past year.
'The prime minister is deeply saddened by the tragic loss of life in the Grenfell Tower and is being kept constantly updated on the situation, ' a spokesman said.
"The potential for a fire to break out in the communal area on the walkway does not bear thinking about as residents would be trapped in the building with no way out", it said.
It emerged in the hours after the incident that residents had repeatedly raised concerns about the building's fire safety. In November a residents' group, Grenfell Action Group, said that only a "catastrophic event" would expose the concerns it had about the building's landlord, according to a blog post from the group.