Mohamed Ali Rasool, 31, was prosecuted after mushrooms and mould were found growing inside the 22-bedroom home in Hyde Park Gate, together with a slew of fire safety hazards.
Single glazed windows had rotten frames, fire doors were damaged and defective, electric sockets were loose and burnt out, and some of the fire alarms had been covered over.
The council said the damp was so bad in parts of the multi-occupancy property that mushrooms were growing on the upper floors.
And in some of the homes residents were cooking on camping stoves due to the lack of adequate kitchen facilities.
Rasool and his property management company, Blackstone Properties Management Limited, were convicted after failing to improve the conditions in the home.
At Westminster magistrates court on November 1, Rasool and Blackstone were both fined £240,000 over the breaches.
Rasool, who was unlicensed to manage properties, refused to appear for the sentencing hearing and was punished in his absence.
He was handed a landlord banning order in January 2022 after a case brought against him by Camden Council over the management of other similarly poorly maintained homes.
Rasool was ordered to pay £95,000 in May last year for safety breaches and unlicensed property management, and he and three companies linked to him were back in the dock in June, in a case that ended in more than £78,000 of fines.
Kensington and Chelsea Council said Rasool’s latest punishment is believed to be a record fine for a case of this type.
“Let this judgement be a clear lesson to other landlords and agents - if you are offering poor quality accommodation we will find you and will come after you”, said Councillor Cem Kemahli, lead member for planning and public realm.
“We want the best homes in the Royal Borough of Kensington and Chelsea. Our landlord licensing schemes are seeking out the bad operators to ensure safer homes for everyone and a fairer market for good operators.”