Former housing secretary Michael Gove has said criminal prosecutions should be brought against Grenfell Tower cladding firms.
Companies that are “still making vast profits without acknowledging their full responsibility” must also be punished financially, he suggested.
Writing in the Sunday Times, Mr Gove claimed attempts to punish Kingspan, Arconic and Celotex when he was in government had been blocked by “bureaucracies”.
There was “insufficient action” from foreign governments on responsible companies based abroad, he said, adding that attempts to restrict imports of their products ran up against the “commercial purism of Treasury Mandarin Brain”.
The final report of the Grenfell Inquiry, published last week, said the west London tower block was covered in combustible products because of the “systematic dishonesty” of firms who made and sold the cladding and insulation.
Kingspan had, from 2005 and even after the inquiry began in the wake of the fire, “knowingly created a false market in insulation” for use on buildings over 18 metres tall (59ft), it said.
Celotex then, in an attempt to break into the market created by Kingspan, “embarked on a dishonest scheme to mislead its customers and the wider market”, inquiry chairman Sir Martin Moore-Bick said.
Mr Gove apologised to the relatives and survivors of the tragedy who were “let down by successive governments, including governments of which I was a part”.
Companies which manufactured materials used on the tower have “still not shown proper awareness of their guilt, contrition for their crimes or restitution for their wrongs”, he added.
“Because Kingspan is based in Ireland, and Arconic’s European operations and Celotex are in France, our jurisdiction was limited. But we were determined to go after them,” Mr Gove said.
The former Conservative Party leadership hopeful pressured Ulster Rugby and Mercedes’ F1 team, asking them to reconsider their relationship with Irish insulation firm Kingspan in 2021.
Last year, he warned shareholders in cladding companies that the firms will face “severe consequences” if no post-Grenfell financial support package is forthcoming.
Mr Gove said taking the “necessary action” against cladding firms “will require toughness… I know there will be voices opposed to robust action”.
“You cannot purchase prosperity at the price of justice. Those who are the guiltiest must pay, and pay the most,” he added.