The Prime Minister has apologised to those affected by the Grenfell Tower disaster on behalf of the British state for the string of failures that led to the fatal fire.

Sir Keir Starmer told MPs that the survivors, bereaved families and the community around Grenfell had been “let down very badly” before, during and after the fire that killed 72 people in 2017.

His apology followed publication of the final report of the inquiry into the disaster, led by retired judge Sir Martin Moore-Bick, which blamed “decades of failure” in government and the construction industry for the fire.

Speaking to the families of those killed in the fire, some of whom were present in the gallery of the Commons, he said: “I want to start with an apology on behalf of the British state to each and every one of you, and indeed to all of the families affected by this tragedy.

“It should never have happened. The country failed to discharge its most fundamental duty, to protect you and your loved ones, the people that we are here to serve, and I am deeply sorry.”

The Prime Minister signalled his support for calls that the companies involved in the disaster be banned from receiving government contracts, and said the Government would support the Metropolitan Police’s investigation into the fire.

He said it was “imperative that there is full accountability, including through the criminal justice process, and that this happens as swiftly as possible”.

Reflecting on a private visit to Grenfell Tower he made two weeks ago, the Prime Minister said it had left him with a “personal determination to make the legacy of Grenfell Tower one of the defining changes to our country that I want to make as Prime Minister”.

Former prime minister Rishi Sunak said the inquiry report was “a damning indictment of over 30 years of successive state failure” and painted a picture of “systemic indifference, failure and in some notable cases dishonesty and greed”.

Associating himself with the apology offered by his predecessor, Baroness Theresa May, in the immediate aftermath of the disaster, he said he wanted to “extend my deepest apologies to the families and victims of the Grenfell Tower tragedy”.

He said: “The state let you down, and it must never do so again.”

Baroness May herself said in a statement that national and local government, regulators and industry “must all acknowledge their part in the history and series of events that led to this tragedy”.

She said the report was “a significant step in providing the Grenfell community with the answers they deserve after 72 people died, deaths that we now know were avoidable”.

Other political figures joined calls for action, with London Mayor Sadiq Khan saying those responsible for the fire should be banned from receiving government contracts and urging the Crown Prosecution Service to bring criminal charges against them.

He said: “The inquiry makes clear in stark terms that all these deaths were entirely avoidable, and that the residents of Grenfell Tower have paid the price for systematic dishonesty, corporate greed and institutional indifference and neglect.”

Liberal Democrat leader Sir Ed Davey said the inquiry’s report should not “become another dust-covered book sitting on a shelf in Whitehall” and demanded dangerous cladding be removed from all buildings “as quickly as possible”.

Sir Ed told the Commons: “The Grenfell disaster is a tragedy that shames our whole society. The report lays bare failings of governments of all parties over decades and on behalf of my party I’m sorry.

“We must all learn from it and do everything we can to change the system to prevent more horrifying tragedies like this in the future.”

Sir Keir, responding to calls for victims of state injustices to be treated with dignity, said: “I don’t want to be back at this despatch box, or any future prime minister back at this despatch box, having a version of the same discussion which is injustice, disregard, not listened to, not taken seriously after the event, too long, too late for people who desperately need justice and that’s what I mean by turning a corner.”