New rules to improve social housing conditions after the fatal Grenfell Tower fire and the death of a two-year-old boy due to mould have become law.
Rogue landlords can be given unlimited fines and social housing managers are required to have qualifications.
Four million households, 17% of all households, live in rented social housing in England.
Housing charity Shelter called the new Social Housing Act “a historic moment” that would affect nine million people.
The government-sponsored Regulator of Social Housing will be able to conduct regular inspections of the largest providers under the law.