Inquiry chair Martin Moore-Bick is to deliver the findings on Wednesday from a six-year investigation that examined how building flaws, lax enforcement of safety standards and mistakes by emergency responders contributed to the shocking death toll in the Grenfell Tower blaze.
The final report might give survivors some of the answers they have long sought, though not prosecutions for those responsible.
Criminal charges are on hold until after the inquiry concludes.
Sandra Ruiz, whose 12-year-old niece, Jessica Urbano Ramirez, died in the fire, said that "for me, there's no justice without people going behind bars".
The Grenfell Tower tragedy horrified the UK and raised questions about lax safety regulations. (AP PHOTO)
"Our lives were shattered on that night. People need to be held accountable," she said.
The fire broke out in the early hours of June 14, 2017, in a fourth-floor apartment and spread up the 25-storey building like a lit fuse, fuelled by flammable cladding panels on the tower's exterior walls.
The tragedy horrified the nation and raised questions about lax safety regulations and other failings by officials and businesses that contributed to so many deaths.
It also prompted soul-searching about inequality in Britain.
Grenfell was a public housing building set in one of London's richest neighbourhoods and many victims were working-class people with immigrant roots.
The victims came from 23 countries and included taxi drivers and architects, a poet, an acclaimed young artist, retirees and 18 children.
Bereaved families worry the report might spread blame too widely to see anyone punished. (AP PHOTO)
The inquiry, announced by the government the morning after the blaze, has held more than 300 public hearings.
An initial report published in 2019, looking at what happened the night of the fire, criticised the fire department for telling residents to stay in their apartments and await rescue.
The advice was changed almost two hours after the fire broke out, which was too late for many on the upper floors to escape.
The final report will examine the "decisions which led to the installation of a highly combustible cladding system on a high-rise residential building".
Grenfell Tower had been covered during a refurbishment with aluminium and polyethylene cladding - a layer of foam insulation topped by two sheets of aluminium sandwiched around a layer of polyethylene, a combustible plastic polymer that melts and drips on exposure to heat.
After the fire, the UK government banned metal composite cladding panels for all new buildings and ordered similar combustible cladding to be removed from hundreds of tower blocks across the country.
The ruined Grenfell Tower still stands and is now covered in white sheeting. (AP PHOTO)
But it's an expensive job and the work has not been carried out on some apartment buildings because of wrangling over who should pay.
The ruined tower, which stood for months after the fire like a black tombstone on the west London skyline, still stands, now covered in white sheeting.
A green heart and the words "Grenfell forever in our hearts" are emblazoned at the top.
Survivors and bereaved families worry the report might spread blame too widely to see anyone punished.
Police are investigating dozens of individuals and companies and considering charges, including corporate and individual manslaughter.
But they say any prosecutions must wait for the inquiry's end and are unlikely to come before late 2026.
