Six hundred tower blocks in Britain could be covered in similar combustible cladding which was blamed for aiding the rapid spread of the Grenfell Tower blaze, Downing Street said.
Urgent tests in the wake of the disaster that killed at least 79 people have so far revealed that the flammable material has been found on at least three tower blocks across the UK, Prime Minister Theresa May told the Commons.
But Downing Street later disclosed that English councils estimated that 600 high - rise buildings used similar cladding to the block in west London that was the scene of last week's tragedy, The Telegraph reported.
Addressing questions about whether any of the blocks will be evacuated, a No 10 Downing Street spokeswoman said: "Obviously nobody will be living in buildings that are unsafe.
They will be rehoused if they need to be. "
May said all local authorities responsible for the flats had been told this, BBC reported.
The announcement comes after the boss of Kensington and Chelsea Council resigned following criticism of the London authority's response to the Grenfell tragedy.
Speaking in the Commons, May said that the council "couldn't cope" in the aftermath of the fire, and that it "was right" its chief executive, Nicholas Holgate, had stepped down.
Councils were told to give details to the government about the cladding they used in the tower blocks by Monday.
The Downing Street spokeswoman said: "So far, three samples have been found to be combustible. "
She said these were part of a "small number" that had been tested and that results are coming back "within hours".
"We are in touch with all the local authorities to encourage them to urgently send us the samples and then we will carry out the checks that we need to see where we are with that, " she said.
Meanwhile, Camden Council confirmed that cladding used on its Chalcots Estate in north London is being removed after tests raised concerns about its safety.
Last week, it emerged that Grenfell contractors had used a more flammable type of material for the outer layer of the cladding, which Philip Hammond, the Chancellor, said was banned in Britain.
The Department for Communities and Local Government (DCLG) later confirmed that the polyethylene filling between the two Reynobond aluminium panels did not pass building regulations for tower blocks over 59 feet and a flame retardant material should have been used instead.