London has the most social landlords with mouldy and unsafe homes in the UK.
Some 20 out of 33 associations and councils called out by housing secretary Michael Gove are in the capital.
In one case, Lambeth council failed to repair a leaking roof for six years, while Newham council failed to remedy damp issues for three years.
Gove wrote to the associations last year, telling them to do better after they mishandled complaints about conditions.
He said: “For far too long too many social landlords have failed to support vulnerable residents across London.
“Our landmark Social Housing Regulation Act is laying the groundwork to introduce life changing reforms – setting strict timeframes to fix hazards through Awaab’s Law, strengthening powers to issue unlimited fines, and providing stronger tenant rights to hold failing social landlords to account.
“Those who seriously neglect their responsibilities will face the consequences and landlords must now step up to provide the safe, warm and decent homes that people deserve.”
Awaab Ishak was a toddler who died in 2022 from a respiratory condition caused by mould, with the event prompting an inquest into poor conditions in social homes.
People living in 11 boroughs were paid more than £200,000 in compensation following special Ombudsman reports into the state of their homes.