Theresa May said on Wednesday June 22 that fire services are in the process of informing residents about hazardous cladding on high-rise flats.
She said fire services are "taking all possible steps to ensure buildings are safe and inform affected residents".
Downing Street said English councils estimated that 600 high-rise buildings used similar cladding to the block in west London which was the scene of tragedy last week.
The government has confirmed that combustible cladding has been found on three tower blocks.
The at-risk buildings are not being identified until the landlords have had the opportunity to inform tenants, according to the Department for Communities and Local Government.
Councils were told to provide the government with details of the cladding used on high-rises by Monday and three samples were found to be combustible.
Flammable panelling on the outside of Grenfell Tower is suspected to have aided the rapid spread of last week’s blaze, trapping dozens inside.