THE author of an explosive new book that rips to shreds Tony Abbott’s performance as prime minister has gone one step further, declaring the former leader “worse than Kevin Rudd”.

The former prime minister has so far not responded well to criticism laid out in journalist and author Niki Savva’s new book, The Road to Ruin: How Tony Abbott and Peta Credlin destroyed their own government, and today the author has added fuel to the fire.

In a blistering column published in The Australian, Savva recommends Abbott “do the decent thing and disappear into the sunset”, going on to criticise his post-prime ministerial performance which so far includes publicly commenting on leaked defence information and facing accusations of leaking it himself.

“What appears to be vengeful behaviour by Abbott has confirmed in (the government’s) minds that they were right to dispose of him,” she writes.

“His decision to publicly comment on leaked classified information that went to the essence of Australia’s strategic defence to undermine his successor was worse than anything Kevin Rudd ever did.

“Whatever his flaws, whatever Julia Gillard’s shortcomings, Rudd did not compromise Australia’s national security to undermine her.”

Since vacating the top job, Abbott has defied hopeful expectations to go quietly. His most recent comments about the delayed construction of submarines, detailed in a draft copy of the defence white paper released last week, have been flagged as his latest attempt to “rubbish” new Prime Minister Malcolm Turnbull’s performance.

Savva goes on to rubbish Abbott’s complaints of “treachery” suggesting what he faced in his ousting didn’t come close to the act of betrayal from “someone within the Liberal Party” of releasing the white paper, and that he had failed to see the reasons for his removal, saying he has preferred to “indulge in prolonged bouts of revenge or self-pity” and “play the victim”.

If Abbott was a victim, it was “of his own actions and those of his chief of staff,” Savva writes.

The former prime minister’s right hand woman Peta Credlin has been in the spotlight since the release of Savva’s book, which doesn’t hold back on criticism of the former chief of staff’s “terrible” treatment of staff.

In her column, Savva offers further unflattering tales of Ms Credlin’s performance and again defends her decision not to go to her or Abbott for comment for the book which was highly critical of them both.

“Abbott rang around staff to find out who was talking to me for my book and to dissuade them from doing so. Having tolerated their terrible treatment, he then sought to hush it up. Say I had submitted­ the on-the-record accounts of mistreatment detailed in the book to Abbott and his former chief of staff for comment, how long do you think it would have taken for them to be called and convinced to retreat or retract?” she writes.

Savva signs off with a stinging line, referring to the criticism she has faced since the book, now in its second reprint, dropped this week.

“So spare me the lectures about ethics, dignity, appropriate behaviour, loyalty or veracity from those who arrived, relatively speaking, a matter of minutes ago, who won something very precious, then destroyed it in record time.”

Ouch.