Residents living in a tower block in south London believe mould growing in their homes is seriously affecting their health.
They say living conditions in Hayesend House, on the Hazelhurst Estate, in Blackshaw Road, Tooting, are "an absolute nightmare".
Campaigners claim 36 out of 56 flats in the block are affected.
Wandsworth Council blame the problem on "a combination of poor ventilation and inadequate use of heating".
A spokesman also said the situation was also confined to "a small number" of flats.
But BBC London found at least 20 flats to be affected by mould.
The residents claim Wandsworth Council has failed to combat the problem properly for the last 20 years.
Resident Carrieann Nash said the mould had been causing chest infections, coughs, colds and bronchitis among her and her two young sons.
"I've been back and forth to the council for five and a half years," she said.
"It's terrible especially for my young son who has cerebral palsy. We are always ill and I'm sure it's because we are breathing in the fumes from the mould the whole time."
"They sent someone out to wash the mould. When he came here he said: 'Sorry love, there is nothing we can do - it needs treatment.'
She said a surveyor then looked at it, agreed that it needed treatment, but he never returned.
Fellow resident Jade Cunningham said she believed the mould was affecting the health of her three-week-old baby.
She said: "It's not just a patch of mould, it's metres and metres of it, cupboards are full of it and mould is over the furniture."
The council spokesman said: "We know of one affected property where the tenant has made the problem worse by removing the wall and door that separated her kitchen and living room and also taped up all her windows and doors preventing any ventilation at all."
Chris Kibbler, Professor of Medical Microbiology, from Royal Free Hampstead hospital, in west London, said some people who have an allergy to particular moulds could experience symptoms such as constant runny and blocked noses, headaches, wheezing and chest infections.