Detectives investigating the massive fire at the Grenfell Tower in west London have released images and video footage from inside the building that show "the scale of the challenge" investigators face in recovering bodies.

The arresting photos show apartment units with almost nothing recognizable left inside, beyond kitchen sinks, laundry equipment and what appears to be a burned out mattress.

One image shows a bathroom, with a blackened sink and bathtub and broken tiles. Another shows the metal frame of an exercise bike amid piles of broken drywall and plaster.

The images were taken by a police recovery team that has been working with members of the London Fire Brigade and the London Ambulance Service to comb through the remains of the charred building.

All the images were taken in units where police know that everyone inside has been accounted for.

London Police Commander Stuart Cundy said his team, along with firefighters, had been working night and day to assess the devastation and attempt to recover bodies.

"It is really important that we are clear about the scale of the challenge facing us as our teams search Grenfell Tower to recover those people still inside and return them to their loved ones,” he said in a statement.

"Whilst our teams have been from the bottom to the top of the tower, we must now carry out a full forensic and systematic search. The conditions due to the fire damage verge on indescribable, which is why this will be such a lengthy operation taking weeks to complete.

He added that teams and families of missing loved ones must prepare for “the terrible reality” that some of those who died in the fire may never be identified due to the intensity of the fire.

Cundy also said that the number of dead or missing in the fire has now risen to 79, but that number may change as the investigation continues, he said.

Cundy said the number includes 30 deaths that already have been confirmed, as well as reports of people who are missing and presumed to have died.