Firefighters spray water on Grenfell Tower. Victoria Jones / PA Wire / PA Images

LONDON — The final death toll of the Grenfell Tower disaster will not be known until next year, the Metropolitan Police has said.

At least 80 people are now known to have died in the catastrophic blaze on June 14. This has risen from 79, with the latest victim being identified as five-year-old boy Isaac Paulous.

But a final figure will not become clear until 2018, as police carry out a painstaking investigation.

Officers updating the media on the investigation said they are "many months from being able to provide an accurate number."

Residents' groups and Labour MP David Lammy have criticised the fatalities number for being unrealistically low, and have even suggested that the true scale of destruction has been suppressed to avoid civil unrest.

Officers said they believe the majority of those who died came from 23 flats in the upper half of the building, which had a total of 129 apartments. Police have yet to make contact with anybody from the 23 flats, leading them to believe there were no survivors. They were distributed between the 11th and 23rd floors.

Officers have contacted at least one survivor in each of the other 106 flats.

The interior of one of the flats in Grenfell Tower. Met Police

Fiona McCormack, a detective chief superintendent orientating the investigation, said a conclusive death toll will be available "only after we have completed the search and recovery operation, which will take until the end of the year."

When pressed on the date for a final figure by Business Insider, McCormack confirmed that a final figure would likely not arrive before 2018.

She explained that police were able quickly to identify a number of victims in the days immediately after the fire. But progress has slowed since then, with Paulous the only new death announced in the past nine days.

Identification work is "complex"

All future identification work will be "much more complex", McCormack said, making it impossible to predict when, or at what pace, the running total may change.

Sources close to the investigation said some remains were so fragmentary, and so badly burned, that it may be impossible to run DNA tests on them.

McCormack said officers have now been in every single flat, and on the building’s roof, as part of the "painstaking, fingertip search."

She said: "We are working very hard to identify everyone who died. But the tragic reality is that, due to the intense heat, there is a tragic reality that some may never be identified."