John Bercow told the BBC 'wholesale change' was needed in Parliament
The Commons Speaker has defended the wholesale reform of the expenses system, saying MPs will have to accept an element of "rough justice".
John Bercow told BBC One's Andrew Marr show that diluting Sir Christopher Kelly's proposals was "not an option".
Some MPs had hoped Mr Bercow would call for the new Independent Parliamentary Standards Authority to review them.
They are angry over losing mortgage interest payments on second homes and the ban on employing family members.
Mr Bercow said: "The public perception of the way in which we operate is so negative that it is necessary to accept a wholesale, fundamental and I think irrevocable change... There's an element of rough justice, but it is necessary."
"Do I agree with Sir Christopher Kelly about the need to abolish state financed house purchase? The answer is that I agree with him 100%," he said.
"Do I agree that MPs should no longer be able to employ family members? The answer is that I do agree that they should not be able to do so."
Mr Bercow added: "The truth is that public trust in Parliament has plummeted. The damage has been seismic."
He said he would not be a "shop steward" for MPs and called Sir Christopher's proposals "workable and proportionate".
Meanwhile, Mr Bercow has denied allegations that he spent £45,581 re-decorating his grace-and-favour apartment in the Palace of Westminster.
The Daily Telegraph reported that this had paid for work, including new wallpaper, furniture and televisions.
It said Mr Bercow had previously admitted spending £20,000 making his apartment suitable for his family, but the true cost was more than twice this.
But the Speaker said he had no say in much of the spending.
In an e-mail to Telegraph editor William Lewis, Mr Bercow said the difference between the two sums was accounted for by the cost of maintenance required by the House authorities.
He stressed he had not personally asked for the work to be done.
It was announced last week that Mr Bercow's wife Sally would stand for Labour for a seat on Westminster Council in next May's local elections.
Mr Bercow, who was a Conservative MP before being elected as Speaker earlier this year, said: "We've become used to Sally being described as a cross between Jerry Hall and Lady Macbeth.
"Now we'll have to get used to her being described as a cross between Jerry Hall, Lady Macbeth and Eva Peron.
"There are people who entertain the old-fashioned, sexist idea that a spouse must do as you tell them.
"My wife is independent of me. She's a free citizen, She's perfectly entitled to stand as a candidate in a local election or any other election."
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