Residents on two housing estates where blocks of flats burned down have been left at risk because of fire stopping measures in buildings being "missing or useless", the BBC has been told.
A block built in Worcester Park in south-west London by the Berkley Group burned down in September.
The BBC has found apparent flaws in two more Berkley Group buildings it is said would allow fire to spread quickly.
The developer said all properties had been "independently signed off".
Since September's blaze, the housing association for The Hamptons estate has temporarily changed its "stay put" evacuation policy following advice from London Fire Brigade.
Former resident Stephen Nobrega told the BBC the way the fire spread "was more or less instant. It was like paper".
Wood is combustible and so fire stopping in timber frame homes is important to prevent the spread of fire.
"You would expect that the materials would contain a fire for a considerable amount of time, but it just didn't happen," Mr Nobrega said.
Although there were no injuries, some residents believed they just about escaped in time.
'Shoddily thrown together'
A number of families lost their homes in the fire while others on the estate said they were concerned their own homes were not safe.
The development has since been on high alert, with security guards patrolling 24 hours-a-day on the lookout for fire.
Metropolitan Thames Valley Housing (MTVH), the housing association that now manages properties in the Hamptons, said it had "fitted smoke alarms in the electrical cupboards of all our blocks".
"We are worried about how our homes are built and if they could go up, we want to be evacuated," a resident, who wanted to remain anonymous, said.
A large fire would be able to spread quickly at another building on The Hamptons site, two independent surveyors have claimed.
Independent chartered surveyor and fire safety inspector, Arnold Tarling, found a large gap between the fire stopping and the cladding on the outside of a building in the estate, which he said would act as a "chimney through which a fire will spread".
"What we have here is a form of fire stopping which just won't do its job," he said.
Greig Adams, a fire safety expert, told the BBC these breaches had "consequences, including a considerable increased risk to life in the event of a fire".
"The provision of effective fire barriers is a mandatory requirement, not an element that can be shoddily thrown together or to cut corners on," Mr Adams said.
A former home owner at the Worcester Park estate has told the BBC she contacted the Berkeley Group nine years ago over safety concerns.
Sheila Majid said she had an independent inspection of her property in 2005 that revealed similar problems with fire stopping and meant "our home did not meet basic fire safety requirements".
She managed to sell her property back to the Berkeley Group, but remained concerned other Berkeley properties had similar problems.
Two years ago a fire at another Berkeley Group-built property on the Holborough Lakes Estate in Kent destroyed a block of flats.
Mr Tarling inspected a loft space at a property in the estate and found similar fire safety problems to those at the Worcester Park estate.
"There needs to be a full investigation of these properties, not only by the contractor but by the authorities," he said.
A spokesman for the Berkley Group said "all properties were independently signed off as building control compliant".
Speaking about the Hamptons fire he said "the police and the fire brigade are still investigating the cause of the fire, which remains unknown" and the group was "making all necessary checks to reassure residents".
A National House Building Council spokesperson said it was the approved inspector for the Worcester Park development and the organisation had "carried out periodic inspections at key stages of a development's construction".
However, they added that "the primary responsibility for achieving compliance with the regulations rests with the builder".
Housing association MTVH said it had since commissioned surveys of all the buildings it owned and managed.
Geeta Nanda, chief executive of MTVH, said: "It's our absolute priority to ensure we provide residents with the support and help they need at this difficult time, and making sure that the homes throughout The Hamptons are safe."
London-based developer Berkley Group has built 19,500 homes in the past five years across the south of England and the Midlands.