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.
More top news
New research calls into question certain common, private treatments whose costs can run into the thousands.
1,209 people were found guilty of 'trolling' offences in 2014 - and 155 have been jailed.
Critics are ambivalent to this year's slate of winners, who were picked in part by American directors Joel and Ethan Coen.