LONDON — Three officials involved with Grenfell Tower, the apartment building where at least 80 people died on June 14, announced their resignations on Friday, as the political fallout over Britain’s deadliest fire in decades intensified.

Nick Paget-Brown, a Conservative, stepped down as head of the council of Kensington and Chelsea, the wealthy London borough that owns the tower, on Friday afternoon. Rock Feilding-Mellen, a Conservative who had been in charge of housing for the council, stepped down as deputy leader.

Hours earlier, Robert Black, the head of the management company that ran the 24-story building and oversaw a renovation that included the installation of flammable cladding, also resigned. The resignations occurred as new evidence emerged that the management company, which started the renovation in 2014, had chosen a less fire-resistant form of cladding to save nearly 300,000 pounds.

The fire, which left hundreds of people homeless, has opened debates over inequality, deregulation, austerity and governance. It is the subject of a public inquiry, led by a retired judge, as well as a criminal investigation. And it has cost several people their jobs, including the council’s chief executive, Nicholas Holgate, who was forced out shortly after the fire.