The Queen and Prince William are visiting a relief centre helping victims of the Grenfell Tower fire.
Their visit to the Westway Sports Centre comes after police say some of those killed in the fire at the west London flats may never be identified.
The BBC understands that at present there could be as many as 76 people missing as a result of the blaze.
Seventeen people are known to have died but that figure is set to rise, with fears the death toll could exceed 60.
Emergency services are to spend a third day searching for bodies in the burnt-out Grenfell Tower in North Kensington.
Fire chiefs say they do not expect to find more survivors, while PM Theresa May has ordered a full public inquiry.
Police said on Thursday that they had launched a criminal investigation into the fire.
The prime minister – who faced criticism for not meeting survivors of the tragedy on a visit to the scene on Thursday – said the victims “deserve answers”.
Mrs May is also due to visit those injured in the fire on Friday morning.
Emergency services were called to the 24-storey residential tower block shortly before 01:00 BST on Wednesday.
Six victims of the blaze have been provisionally identified.
However, Metropolitan Police Commander Stuart Cundy said there was “a risk that sadly we may not be able to identify everybody”.
Asked about the number of dead, he said he hoped the death toll would not reach “triple figures”.
He added: “We as the police, we investigate criminal offences – I am not sitting here and saying there are criminal offences that have been committed, that’s why you do an investigation, to establish it.”
The leader of Kensington and Chelsea Council – the authority that owns the tower block – told BBC Two’s Newsnight it would not use the type of cladding fitted to Grenfell Tower in other buildings in the borough.
The cladding – installed on the tower in a recent renovation – has come under scrutiny, with experts saying a more fire resistant type could have been used.
Councillor Nicholas Paget-Brown also said there had not been a “collective view” among residents in favour of installing sprinklers during the renovations.
Meanwhile, Conservative MP Chris Philp said the public inquiry should produce interim findings to ensure swift action can be taken if residents in other tower blocks are at risk.
On Thursday, the first victim of the fire was named as Syrian refugee Mohammed Alhajali, 23.
The Syria Solidarity Campaign said Mr Alhajali, a civil engineering student, had been in a flat on the 14th floor when the fire broke out, and had spent two hours on the phone to a friend in Syria.
He had been trying to get through to his family while he was waiting to be rescued.
His older brother, Omar, told the BBC he had lost Mohammed on the way out of the building.
Stories of how people managed to escape have also emerged.
Christos Fairbairn, 41, a resident who lived on the 15th floor, described how he collapsed while fleeing the building, only to be rescued by a firefighter.
Meanwhile, it has emerged that Elpidio Bonifacio, a partially blind man in his 70s, was rescued from his 11th-floor flat after having been seen at the window waving a jumper.
His son Gordon, 41, said on Facebook that his father was now in intensive care.
A political row also erupted, after the prime minister made a private visit to the scene, where she spoke to London Fire Commissioner Dany Cotton and members of the emergency services.
However, unlike Labour leader Jeremy Corbyn and London Mayor Sadiq Khan, Mrs May was not thought to have spoken to families and residents.
Downing Street said the purpose of her visit was to get a briefing from emergency services and to ensure that they had the resources they needed.
She later announced a public inquiry, but former cabinet minister Michael Portillo said the prime minister “didn’t use her humanity”.
Posts on social media suggest residents are planning to march from Grenfell Tower to Kensington and Chelsea town hall on Friday afternoon