The criminal charges for the Grenfell Tower fire are unlikely to be brought before the "second part of 2021", police said.
Scotland Yard said he would pass a file to prosecutors after the second phase of the continuing public inquiry into the disaster.
The force said that "it would be wrong" not to take into account the evidence provided to the independent hearing.
A total of 72 people were killed as a result of the fire in June 2017.
Detective chief Det Supt Matt Bonner said the time lines of the investigation and the police probe were "inextricably linked".
He said that agents must "consider all relevant information", including evidence and survey results, for their investigations to be "considered complete and complete".
"Longer than expected"
Previously the survey had stated that it was unlikely that the second phase of public hearings would start before the end of 2019.
Scotland Yard said: "The evaluation of the Met is that any file submission to the Crown Prosecution Service is unlikely to be before the last part of 2021."
Det Supt Bonner said the agents were in regular contact with the survivors of Grenfell and the bereaved families and had informed them of the chronology.
"I know it's longer than some might have foreseen, but the police must ensure that all available evidence is taken into consideration before any file is submitted to the CPS," he added.