Former Labour leader Neil Kinnock has attacked "repellent" Damian McBride for how he acted while serving as Gordon Brown's adviser and for publishing a tell-all book on the eve of the Labour Party conference.
Speaking to The Huffington Post UK in Brighton on Tuesday morning, Kinnock said McBride "has simply made himself even smaller, which makes him infinitesimal" by his actions.
"It's appalling. Obviously the guy is repellent. To do what he did is entirely wrong. And to produce the book now in order to maximise damage or attempted damage for the Labour Party is appalling," he said.
However Kinnock predicted voters would not be too affected by the internal-Labour row: "What he and some of the press have miscalculated is that the degree of importance which the general public attaches to it, they could not give a damn."
Kinnock, who led Labour from 1983 to 1992 and now sits in the House of Lords, has been a strong supporter of Ed Miliband and told party activists following his 2010 leadership victory: "We've got our party back."
The Labour peer said he hoped Miliband would use his speech to party conference today to show and "understanding of the great centre ground, its needs and its hopes".
He said: "And showing that we now have the policies that address those needs and those hopes. I am certain given his instinct that is what he will do."
Miliband had something of a dire summer, with critics both within and without Labour raising concerns that the leadership had not set out enough concrete policies to convince voters to start coming back to the party in time for the 2015 election.
Kinnock said it was "always a dilemma" about when to start making policies public. "I can sympathise with this, of disclosing core policies substantial amount of time before an election and giving the government a chance to steal some of them or to misrepresent others and so timing is important," he said.
"I think what they have done in restraining the announcement of most policies until now, providing five or six absolutely key policies on investment on social justice now, and then filling in details as we get to the election is absolutely the right direction."
Miliband has also been involved in a spat with the trade unions over his plans to reform their relationship with the party. However Kinnock, who famously confronted the left-wing Militant tendency within the party in the 1980s, said there was no parallel "whatsoever" between then and now.
"Ed is seeking reform and modernisation of the relationships within the Labour Party. What I had to do was to exclude people who brought the parry into disrepute by being a secretive organisation that had infested the Labour Party a different task all together."