The Grenfell Tower inquiry will get to the "full truth" about the tragedy, looking at what happened on the day of the fatal blaze and the regulatory regime which may have contributed to it, Justice Secretary David Lidington vowed.
Mr Lidington, who as Lord Chancellor has a duty to speak up for the judiciary, defended the appointment of Sir Martin Moore-Bick to lead the inquiry despite calls for him to stand down from some Grenfell survivors and Labour politicians.
Retired Court of Appeal judge Sir Martin wants to "get to the truth and see justice done" and evidence taken in his inquiry could be used by police and prosecutors considering criminal charges, Mr Lidington said.
On BBC One's Andrew Marr Show, Mr Lidington rejected claims that the scope of the inquiry would be narrowed in order to avoid political embarrassment for the Tories over cuts to local government spending.
He said the disaster, which left at least 80 dead, should cause "soul searching" for all political parties.
"I think when we have looked at what's come out in the last few weeks since the Grenfell tragedy, with tower blocks in authorities of all political colours failing the combustibility test, fire regulations - if we want to start pointing fingers - brought in under the Blair government.
"All political parties, I think, need to do some soul searching about this. I'm very confident we will get some terms of reference that will get to the truth ... not just in terms of what happened on that particular day but what the regulatory decisions and the responsibilities that led up to that were."
Mr Lidington stressed that Sir Martin's inquiry would not look to apportion criminal blame - that was for the police investigation and any subsequent prosecution.
"We have got to be careful about one thing, because this has come up in the debate about the scope of the inquiry. The inquiry doesn't look into criminal guilt or innocence. There's a separate police inquiry going on into that matter already."
But he added that the inquiry would have significant powers.
He said: "It's up to Sir Martin to determine exactly how the inquiry goes. Of course he can compel any witness to attend under pain of a criminal offence and he can compel witnesses to give evidence under oath as well.
"Evidence in his inquiry can, if the police and Crown Prosecution Service think it justifies it, later be used for a criminal investigation, prosecution as well.
"So I think that he is very, very determined to get to the full truth about this."