The Metropolitan Police will ask the Crown Prosecution Service to consider charging up to 57 individuals and 20 companies over the Grenfell Tower fire disaster.
In an update at New Scotland Yard, the force said it would submit evidence files to the CPS by the end of September this year.
A final decision on whether to bring charges could take until June 2027 - 10 years after the fire in west London, which killed 72 people. If the CPS does decide to prosecute, any trials are unlikely to begin before 2029.
A spokesman for Grenfell United, which represents some of the bereaved families and survivors, said the development was "an important step in a process that has already taken far too long".
The Grenfell Tower fire was caused by a chain of failures by governments, "dishonest" companies and shortcomings in the fire service, a public inquiry found.
Operation Northleigh, the £150m probe into the disaster of 14 June 2017, has examined the actions of 15,000 people across 700 organisations in the largest and most complex investigation ever carried out by the Met Police.
Grenfell United called for no further delay to proceedings and said those responsible must be held to account.
The group said: "For our community, this is not news we meet with celebration. We meet it with caution, grief and determination. We have waited almost a decade for accountability."
It added that the Ministry of Justice and the government must ensure the courts were properly resourced so any prosecutions linked to Grenfell could be heard swiftly.
The CPS has already begun reviewing some of the evidence.
Garry Moncrieff, from the Metropolitan Police, said the final number of people and organisations being considered for charge was "not expected to vary a lot" when the full submissions were made in September.
He said officers had gathered extensive material over several years as part of the inquiry.
"We have gathered strong evidence," Moncrieff told reporters at a Scotland Yard briefing.
He added: "It is important that we do it once and do it right."
The Met Police chose to wait for the findings of the Grenfell Tower fire public inquiry before looking into the potential for criminal charges.
The inquiry began in 2017 and was concluded in 2024. Moncrieff said this had added time to the investigation but had not damaged it.
He would not be drawn on how likely it is that charges will be brought, but said investigators were building full-scale replica sections of the tower at a cost of £2m in preparation for possible court proceedings.
Moncrieff said forensic teams spent 14 months at the site gathering evidence and have since examined material linked to hundreds of companies and thousands of individuals, as well as evidence from the public inquiry.
Police said 165 million electronic files had been gathered and searched, while 14,400 witness statements have been taken.
So far, 15 of the 20 case files have been passed to the CPS for advice.
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