Police expect the death toll from the Kensington flat fire to rise above the 12 they have been able to confirm.

London Fire Brigade officials have been able to search most of the building and firefighters are now on the top floor of the 24-storey building. But they cautioned the process will take them time.

The death toll has already doubled in the last few hours and the news is predicted to become more gloomy in the hours ahead.

“This remains an active operation but sadly I can confirm there are 12 people that have died in this truly shocking fire,” said a police spokesman.

“This is a complex operation and I anticipate the number will increase beyond those 12.

“From a police perspective we must identify and account for everyone.

“We’ve taken hundreds of calls and experience shows us, its very challenging to put a number on those that are unaccounted for. If you’ve reported someone missing and they’ve been found safe and well please contact us.

“This is going to be a long operation.”

London Fire Brigade officer Steve Apter confirmed that – at the height of the fire – more than 250 firefighters were on the scene.

That number has decreased by the fire is still being fought.

“This was an unprecedented fire in terms of scale, speed and strength,” he said. “It’s a traumatic and difficult incident and it’s still a live incident.

“We will be here until the job is done, working alongside our colleagues from the emergency services.

“The fire continues to provide challenge but our firefighters have searched almost all the building thanks to their professionalism and bravery.”

Nearly 80 people were treated for injuries at six different hospitals and 20 are in critical condition, according to NHS officials.

On a day of unimaginable grief and worry, scores of people remain missing, with friends and relatives desperate for news.

Debris from the fire is strewn around adjacent streets as the horror stories were told and retold by eyewitnesses, some with no home to go to.

One resident broke down in tears as they recounted how a woman thought she’d escaped the blaze with her six children, only to reach safety and discover two were missing.

Another said how they’d seen a baby thrown from an upper floor and caught by a bystander. Resident Mahad Egal said he saw people jumping from the upper floors to avoid the flames.

“We could see people standing on windows asking for help and screaming,” said local resident resident Fatma Muhammad, 53.

“At four in the morning people were still in that window waving. The whole night we were crying watching.”

The fire took hold shortly after midnight and soon engulfed all floors of the Grenfell Tower in Kensington, which is home to hundreds of residents.

The tower, built in 1974, recently underwent a £9 million redevelopment but a local community group had been expressing concerns about its fire safety for the past four years.

London mayor Sadiq Khan insisted he would demand answers after reports fire alarms didn’t work and residents had been told they were safer to stay inside and await rescue – advice which will have cost lives.