Labour's former spin doctor Damian McBride said he was "ashamed" of the way he treated Labour politicians he saw as rivals to Mr Brown, but he insisted he did not break the law, and said he would be happy to speak to police if they decide to look into complaints from a Conservative MP.
Mr McBride said he did not believe that Ed Miliband and Ed Balls were aware of the details of his briefing activities when he was working for Gordon Brown and added that he was ready to give up his pension if the civil service felt he should.
Mr McBride said:
"I feel ashamed and sorry to those individuals whose careers I affected and even more so to the innocent bystanders that got in the way - special advisers who lost their jobs as a result of them being pushed out of government, people that were mentioned in the context of these sleazy stories."
Damian McBride has returned to this conference a little bit like a bad smell.
I should say for the record that I never did any business with Damian McBride because I thought that his way of doing things was very very toxic right from the start.
I think there are certainly people who have questions to answer about it not least Gordon himself, who employed him for such a long time. Is it really fair to lay all of that at Ed Balls and Ed Milibands door?
I'm not sure, but what I would say with reasonable confidence is that I don't think that is going to change the atmosphere around them now.
The former spin doctor Damian McBride has given an interview to the BBC's Newsnight programme about why he chose to write about the political infighting during the Gordon Brown era.
I know many people in the Labour movement think I'm a traitor for publishing a book lifting the lid on some of that feuding, especially at party conference, but I believe if Labour's going to avoid repeating its mistakes it's got to learn from its past, exorcise its demons, and make sure that when it says those days are over, it means it.
In opposition, any sense of disunity or disagreement between Miliband and Balls - any repeat of the Blair/Brown feud - would be fatal to Labour's election chances.
If anything, I hope my book will act as a sobering reminder of those risks.
The Conservative MP Alun Cairns has asked the Metropolitan Police to investigate the former Labour spin doctor Damian McBride, to see if he leaked documents in violation of the Official Secrets Act.
Mr Cairns told the head of the Met Sir Bernard Hogan How that he is "deeply concerned serious offences may have been committed".
His fellow Tory MP Henry Smith has written to the Whitehall watchdog to see if Mr McBride broke any rules of the civil service when in his handling of sensitive documents while working for the Treasury.
Mr McBride's account of his actions clearly shows that his behaviour directly contradicted the Civil Service values of integrity, honesty and impartiality.
It is clear...that Mr McBride broke the Code on numerous occasions, briefing out confidential government documents and briefing against other members of the government.
– Henry Smith MP letter to First Civil Service Commissioner Sir David Normington