Cladding on 27 tower blocks in 15 council areas in England has failed fire safety tests, the government says.
This comes after Camden Council became the first authority to evacuate residents over fire safety concerns, asking people living in four high-rise buildings to leave late on Friday.
The council said it had no option but to move residents of 650 flats on the Chalcots estate while work takes place.
Theresa May said “necessary” steps will be taken to find people accommodation.
By Saturday morning, 83 people had refused to leave their homes.
The council’s Labour leader, Georgia Gould, said the council had acted “as swiftly as we possibly can” to ensure people’s safety.
Ms Gould said the fire service “told us they could not guarantee our residents’ safety in those blocks”.
“I know it’s difficult, but Grenfell changes everything and I just don’t believe we can take any risk with our residents’ safety and I have to put them first.
“I offered to pay for fire stations to be stationed outside all of those blocks so we could have a couple of days to get the work done but the message was there was absolutely nothing I could do to make those blocks safe that night.”
She said that if people still choose to not leave their homes then it would “become a matter for the fire services”.
Mrs May said: “We are making sure that the authority has the ability to do what is necessary to ensure people have somewhere to stay and that the work is done so that those tower blocks will become safe for them to return to in future.”
Other high-rise buildings, such as some used by the NHS, are also being tested.
The Department for Communities and Local Government have named six of the 15 local authorities where high-rise buildings have failed fire safety tests as:
Camden – where residents have been evacuated from four blocks on the Chalcots estate
Brent – where a housing association tower block, Elizabeth House, has cladding but London Fire Brigade advises it is not a risk
Hounslow – where Clements Court tower in Cranford is to have outer cladding removed
Manchester – where 78 panels are being removed from one area of the Village 135 development in Wythenshawe
Plymouth – where three blocks on the Mount Wise Tower estate were found to have cladding made from similar material to Grenfell Tower
Portsmouth – where the city council is removing cladding from Horatia House and Leamington House in Somerstown
The estate’s cladding is similar to Grenfell Tower in west London, where a fire is feared to have killed 79.
The Metropolitan Police say manslaughter, health and safety, and fire safety charges will be considered in relation to that blaze.
Chalcots was refurbished between 2006 and 2009 by the same firm, Rydon, that oversaw work at Grenfell Tower in 2015-16.
Camden Council says it will remove external thermal cladding from five tower blocks on the Chalcots estate.
It also said there were concerns about the insulation of gas pipes going into flats, and fire doors.
The council initially announced the evacuation of one tower block, Taplow, but later extended the move to all five tower blocks it had checked.
In the early hours of Saturday morning, the council then announced that one of the five – Blashford – did not need to be evacuated, and residents could return, because it is smaller and has “several different design elements”.
Children jump on the climbing frames and kick around a ball in the playground outside Swiss Cottage leisure centre.
It would seem like a typical Saturday morning for families, except many are laden with bags or suitcases after leaving their homes.
Locals say they are weary, after a chaotic night of mixed messages about whether or not they can stay in their homes.
Pamela Woodward, 72, and her husband are walking away from the centre with two black suitcases, after being told they will be put up in a hotel.
They stayed in their tower block last night after being told at 2am that someone would be back to collect them – but no-one returned.
Pamela said: “It’s disgusting. We’ve lived here for 30 years and there’s been two fires since the cladding was fitted and they’ve all been contained.
“I think there has been a big cock-up. I feel terrible. I just want to be at home. I’ve been up all night waiting for them.”
The council has secured 270 hotel rooms so far. Emergency accommodation was set up at Swiss Cottage leisure centre and at the Camden Centre in King’s Cross.
“We’re encouraging all residents to stay with friends and family if they can, otherwise we’ll provide accommodation,” the council said.
The decision to evacuate the buildings was made at 18:30 BST on Friday.
The work is expected to take three to four weeks. Residents will be allowed in at the weekend to collect more possessions under escort from the fire brigade.
Teacher Kim Price, who lives in Blashford tower with her 14-year-old son, said: “We’ve had two letters in two days saying ‘you’re not safe’ then ‘you’re safe’. I don’t really know what to do.”
Edward Strange said the evacuation was a “complete overreaction”, given that two previous fires in the block were easily contained. “I’ve got a young daughter, a wife and a cat, I’ve also got a job. They said it’d take four to six weeks. If the council says four to six weeks it’ll take four to six months.”
Peter Bertram, 94, who has lived on the estate for 46 years, said: “My neighbour told me ‘Get this and that’. It happened so quick, I don’t have the energy for that now.”
Bob O’Toole, chairman of Chalcots Estate residents’ association, told BBC Breakfast that contractors had been working overnight in several of the tower blocks.
“A lot of people are annoyed because of the way [the evacuation] was done. They’re saying it was left too late in the evening. But Camden Council didn’t get the information till late, and they acted on that as quickly as possible.”
One resident, Belinda, says she is among a number of tenants who are refusing to leave their flats “because we think it’s unnecessary and some don’t know what they will do with their pets.”
She said council lawyers accompanied by police have advised her to vacate the building, but added: “They know they can’t force us to leave without legal documents which will take them time to put together.”
Communities Secretary Sajid Javid said the local fire service for the Chalcots Estate found multiple other failures in fire safety and, as a result, had made “this quite correct decision”.
“Public safety is absolutely paramount, you cannot put a price on people’s lives. So local authorities have to do whatever it takes to get their buildings safe.”
examined this week
Labour leader Jeremy Corbyn said councils across the country needed to deal “swiftly and effectively with the scale of the fire safety challenge” posed by the Grenfell Tower fire and the government’s emergency Cobra committee should meet to plan a stronger response.
“This is now a nationwide threat and the prime minister needs to get a grip,” he added.
Liberal Democrat President Sal Brinton, a member of the All-Party Parliamentary Fire Safety and Rescue Group, said: “This is a civil emergency. The government must guarantee funding for local councils to do everything necessary to keep people safe and compensate those who have had their lives disrupted.”
Local MP Tulip Siddiq backed Camden Council’s decision to evacuate the estate.
“London Fire Brigade said immediate action needed to be taken to evacuate the residents. It’s not an ideal situation and I understand residents are feeling frustrated… But the safety of our residents needs to come first and if the towers are deemed unsafe we cannot have them staying there overnight,” the Hampstead and Kilburn MP said.
Camden Council agreed a contract with Rydon Construction to refurbish the Chalcots estate in May 2006 at a cost of £66m.
The work took more than three-and-a-half years. Five towers received new cladding and 711 flats were modernised with new wiring, heating, kitchens and bathrooms.
David Clixby, who lives in a nine-storey council tower block in Billingham, Cleveland, has contacted the BBC to say residents have been notified that the building has been “partially clad” in combustible cladding.
“We are being allowed to stay in our flats until the work starts on Monday, as the fire services have said they are safe enough for us to stay. The council have put 24-hour security in each block until work starts.”