A number of events are taking place across London to mark five years since the disaster.
A memorial service has taken place at Westminster Abbey to mark the fifth anniversary of the Grenfell Tower fire.
Seventy-two people were killed by the blaze in west London on 14 June 2017.
At 11:00 BST the multi-faith memorial service began with the names of the victims read out followed by a reply of “forever in our hearts” from the congregation.
The Dean of Westminster, the Very Reverend Dr David Hoyle, said the loss was “still vivid and sharp”.
Former prime minister Theresa May, Mayor of London Sadiq Khan and Housing Secretary Michael Gove were among those in the congregation.
Dr Hoyle opened the service by noting the loss and anguish was “still vivid and sharp”, as the congregation gathered “in sorrow and in pain”.
“We gather as those who look for justice and a renewed commitment to securing safety in our homes; safety in times of fire,” he said.
“Grateful for the support of the communities and individuals that have sustained the bereaved and the survivors over the last five years, we meet in faith and hope looking to a better, safer, surer future.”
Journalist Jon Snow was invited to speak at the service.
“Grenfell, set in the richest borough in Britain, speaks to the grotesque inequality with which our society has been riven,” he told the service.
“We must now confront the issues raised by the Grenfell disaster.”
Lawyer Imran Khan, who also addressed the congregation, said: “For the residents of Grenfell, their home wasn’t their castle, it was their deathbed.”
At the scene
BBC News correspondent Nick Johnson
From scarves and flowers, to altar cloths and decorations, Westminster Abbey was adorned in green as hundreds gathered for this memorial service to remember those who lost their lives on this day five years ago.
At the very heart of the service was a sense of unity and remembrance. Members of the congregation held hands, comforting those who were weeping, as the names of each of the 72 victims were read out.
We heard from Marlene Anderson.
Her father Ray “Moses” Bernard lost his life in the fire. His daughter spoke of her trauma and how she and other family members often relive that night.
Perhaps the loudest round of applause came after lawyer Imran Khan’s speech. He spoke of his disbelief over a lack of criminal charges and described the public inquiry into the fire as ineffective.
As the congregation filed out of the Abbey, 72 candles were left flickering on the altar, a reminder that the Grenfell victims will never be forgotten.
Elsewhere in the capital, a 72-second silence will be observed at the Westfield shopping centre in Shepherd’s Bush at 14:00.
Organisers also say people will also gather at Grenfell Tower for a multi-faith service in the afternoon.
Fencing will be removed from the tower to allow for the laying of flowers and wreaths.
At 18.30, survivors will join bereaved families and community groups for a silent walk from the base of the tower.
Firefighters from across the country will form a guard of honour during the walk.
Natasha Elcock, chairwoman of campaign group Grenfell United, said: “This week will be a difficult week for everyone affected by the Grenfell Tower fire.
“For many of us the events five years ago are still so raw in our minds and our losses remain heavy in our hearts.”
Raheleh Afraseibi, who lost her mother Fatemeh and aunt Sakineh in the fire, said the “catastrophe is never-ending for us”.
She said: “We don’t want them to just say ‘Never forget’, we want it cemented in some way.”
Members of the Grenfell Next of Kin group, which also represents those bereaved by the tragedy, said they did not want their loved ones’ deaths to have been in vain.
Pete Wolfenden, a firefighter who responded to the blaze, said “the thoughts and wishes” go out from all London firefighters and fire control staff to those affected by the fire.
London fire commissioner Andy Roe said he had found the strength and dignity of the Grenfell community “humbling and inspiring”.
He added: “I give my commitment that we will continue to listen and make changes to our service and work to drive improvements in the built environment to ensure such a tragedy can never happen again.”
While a criminal investigation into the disaster is under way, the Met Police has said no prosecutions will be brought until the public inquiry is finished and its findings are published.
So far, fewer than half of the recommendations from the inquiry have been adopted into law, according to the Home Office.
The process has left survivors and bereaved families feeling unable to move on.
Earlier this month, the government imposed a total ban on the specific type of cladding that allowed the blaze to spread so rapidly. Previously, the ban applied only to buildings higher than 11m (36ft).
The government first received data demonstrating the danger of polyethylene-cored cladding in 2002.
The Department for Levelling Up, Housing and Communities (DLUHC) said it was taking steps to ensure buildings were safer.
A spokesman said: “The Grenfell Tower tragedy must never be allowed to happen again and our thoughts are with the bereaved families, survivors and residents.”