80 people are dead or missing following the fire earlier this month
Police in the UK say 80 people are dead or missing following the Grenfell Tower fire earlier this month.
However, they are warning that it it will be "many months" before they can provide a number that "accurately represents the total loss of life".
Detective Chief Superintendent Fiona McCormack said there are 23 flats where investigating teams "have been unable to trace anyone alive who lived there".
She explained: "At this stage, we must presume that no one in those 23 flats survived - that would include those who lived there or any anyone who was visiting them.
"We are in contact with some next of kin and some friends. I cannot say today with any certainty the total number of people who were in those 23 flats on the night."
She added: "At the heart of our investigation we are seeking to establish what happened to each and every person who lost their life - each and every personal story is deeply distressing. This is what my 250 detectives are working so hard on."
Meanwhile, Jeremy Corbyn said the Grenfell fire had "exposed the disastrous effect of austerity" as he clashed with Theresa May during the first prime minister's questions since the UK election.
The Labour leader said the disaster should serve as a "wake-up call", while Mrs May hit back with an attack on the Tony Blair years.
Mr Corbyn faced shouts of "shame on you" from Tory backbenchers as he attacked the Tory austerity, while Mrs May was heavily criticised for her deal with the DUP.
Mrs May said that cladding samples from 120 tower blocks, in 37 local authority areas, have now failed flammability tests - a 100% failure rate.
Mr Corbyn said: "When you cut local authority budgets by 40% we all pay a price in public safety.
"What the tragedy of Grenfell Tower has exposed is the disastrous effect of austerity," he added, to jeers from the Conservatives.
"This disregard for working-class communities, the terrible consequences of deregulation and cutting corners - I urge the Prime Minister to come up with the resources needed to test and remove cladding, retrofit sprinklers, properly fund the fire service and the police so that all our communities can truly feel safe in their own homes.
"This disaster must be a wake-up call."
Mrs May hit back, saying: "The cladding of tower blocks began under the Blair government."
She went on to say the Labour government introduced changes in the regulations on safety inspections.