The number of tower blocks to have failed fire safety tests in the wake of the Grenfell tragedy has leapt to 60 in latest figures released by the Government.
Cladding from high-rise flats in 25 local authority areas has now proved to be flammable in the urgent safety review after at least 79 people died in a fire at the west London block.
Officials said every single sample to have undergone checks so far has failed.
The new figure is nearly double the 34 blocks found be wrapped in flammable cladding in the previous update given on Saturday.
Thousands of residents living in Doncaster, Norwich, Stockton-on-Tees and Sunderland are among the latest to be affected.
Manchester, Plymouth and Portsmouth have already been named.
Islington, Lambeth and Wandsworth joined Barnet, Brent, Camden and Hounslow on the growing list of London boroughs to have potentially unsafe flats.
A total of 11 other areas are yet to be named.
Hundreds more blocks are still yet to be tested, with the Department for Communities and Local Government estimating that around 600 residential tower blocks nationally are fitted with cladding.
Officials said that local authorities and fire services in affected areas had been contacted with support.
"All landlords and fire and rescue services for these local authorities have been alerted to the results and we are in touch with all of them to support and monitor follow-up action," they said.
They have urged for cladding samples to be sent as quickly as possible, adding that lab facilities can work around the clock to process up to 100 tests per day.
The Government is facing calls from councils to step up its funding to help with evacuations and renovations of tower blocks thought to be at risk of fire.
London mayor Sadiq Khan today said it was "crucial" that the Government to provide support to fix blocks that were unsafe.
"It can't right in 2017 there are Londoners sleeping in what are ostensibly death traps," he said.
Meanwhile, Camden council in north London has evacuated hundreds of residents from five towers in the Chalcots estate over safety concerns.
It has emerged that the towers were fitted with potentially flammable cladding and also had a series of other fire safety failures.
A number of residents have refused to leave, and the council is considering taking legal action to remove them.