LONDON -- The chief executive of a group that managed the now-charred Grenfell Tower apartment building in London has stepped down, saying he wants to "concentrate on assisting with the investigation" into the fire that left at least 80 people dead.

The Kensington and Chelsea Tenant Management Organisation (KCTMO) said in a statement Friday that CEO Robert Black wanted to step aside to, "ensure that the KCTMO can continue to provide services" to the thousands of other public housing units it manages in the area. The organization says it manages 10,000 public housing units on behalf of Kensington and Chelsea Council, an affluent west London borough.

His departure from the top role at the KCTMO comes a day after the city council was widely rebuked for calling off its first public meeting on the disaster, because journalists turned up.

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Prime Minister Theresa May's office rebuked Kensington and Chelsea Council on Friday for shutting down the meeting on the fatal high-rise fire -- the first gathering of the council cabinet since the blaze.

She cited a ruling from Britain's High Court.

"The High Court ruled that the meeting should be open and we would have expected the council to respect that," the prime minister's office said in a statement.

The council, which owns Grenfell Tower, also faced criticism Friday after reports that it used more flammable materials in renovating the building to save money.

A report Friday in the Times of London cited documents showing that the council chose aluminum composite panels for the renovation project rather than a non-combustible zinc alternative. The decision saved the council around 300,000 pounds ($390,000), the Times said. The report said an additional £5,000 would have bought more fire-resistant aluminium siding panels.

The panels are part of the exterior cladding blamed by many experts for allowing the fire to rapidly spread throughout the building, trapping many residents in their homes before firefighters could reach them. At least 80 people died, but police have made it clear that number could still rise, and they may not be able to clear the entire building until the end of the year.

At least 149 other high-rise buildings in Britain have failed fire-safety tests mandated in the immediate aftermath of the Grenfell Tower fire -- all of those for which test results have come back. Scores more are yet to be tested.

The Times report came after council leader Nicholas Paget-Brown on Thursday abruptly ended the first Cabinet meeting since the June 14 disaster. Paget-Brown initially sought to bar the media from the meeting, then scrapped the session after media organizations won an injunction allowing reporters to be present.

Paget-Brown said that the presence of the media would "prejudice" a public inquiry into the disaster planned by the central government.

Opposition Labour Party Councilor Robert Atkinson, whose ward includes Grenfell Tower, challenged Paget-Brown loudly, yelling: "An absolute fiasco, this is why I am calling for your resignation."

Before the meeting was closed, Paget-Brown acknowledged that things had gone wrong in dealing with the aftermath of the fire.

"I realize the council has come in for much criticism for its response," he said. "I will acknowledge this and apologize for what we could have done better."