For 12 of the 15 years that he presented The 7.30 Report, the single most constant presence in Kerry O’Brien’s working life was John Howard.

“Every few weeks, and often more frequently, we’d sit down to yet another interview,” the former ABC broadcaster writes in his upcoming memoir. “It became a kind of endurance test, particularly given the intense, sustained and at times malevolent attacks on me and my colleagues’ professional integrity during much of that time.”

Now retired from the news business and released from the obligations of public broadcasting, O’Brien is returning fire in Kerry O’Brien, A Memoir, an 880-page tome that traverses five decades of journalistic life.

Among observations on his own career – including celebrity interviews, his early years in television and a stint as Gough Whitlam’s press secretary in opposition – O’Brien offers a searing analysis of Howard’s years in office.

While crediting Howard for his willingness to face tough questioning “far more than he ducked it”, O’Brien concludes that the distinguishing feature of Howard’s prime ministership – especially the first half – was divisiveness.

“What struck me time and again as I trawled through my interviews was the surprising number of issues that flared up, not just because they were intrinsically emotive but also, I believe, because of the confrontational way Howard dealt with them,” he writes.

Speaking to The Saturday Paper this week, O’Brien says that if longevity in office is a measure of success, Howard – whom he says he always liked personally – was certainly successful.

But O’Brien suggests success in politics should be judged differently.

“If you look at the mark that he has made on the country and the impact that he has had, then I think his success falls away significantly,” he says.

“And I’m talking particularly about issues like social cohesion – issues where the kind of leadership that I believe was required was to bring the country with you in your decision-making, rather than divide the country on the way through. Probably the single most powerful picture or pattern that comes through of the Howard years in this book is the pattern of divisiveness.”

While Howard supporters will certainly disagree with O’Brien’s critique, the former PM’s detractors have long expressed similar views. In support of his argument, O’Brien cites Howard’s handling of a series of issues: the emergence of one-time Liberal and now One Nation senator Pauline Hanson; waterfront reform; native title and particularly the response to the High Court’s Wik judgement; asylum seekers, including the incident involving the Norwegian freighter Tampa and the so-called “children overboard” affair in 2001; and Australia’s involvement in the 2003 Iraq war.

“These were all illustrations,” O’Brien says. “Whether he set out to do so … I think it’s pretty clear that he saw these issues as there to be exploited to help him win elections, particularly in 2001. I think that we still see a damaged country … we see a divided country, partly as a result of that. Those issues were parts of a mosaic that we now see today, of what Australia is.”

He likens Howard to English cricketer Geoffrey Boycott, whose playing career spanned two decades from the early 1960s – “a notoriously dour, risk-averse batsman who played a dead bat to many balls, but everything loose was usually hit to the boundary”.

“Boycott might have been slow to score, but he also made a lot of runs,” he writes. Howard “pitched himself as the safe, dependable pair of hands who would lead Australians back into a ‘comfortable and relaxed’ state after the turbulence of the Hawke–Keating years and the recession”.

But he queries how relaxed the nation became as a whole.

O’Brien’s analysis of Howard is not all condemnation.

He praises the swift move to tighten gun control in the wake of the 1996 Port Arthur massacre in Tasmania. He calls it courageous – “inspired” – saying Australia remains safer for it and “nobody can take that away from John Howard”.

But in contrast, on independence for East Timor – another of the successes Howard has claimed – he says the government “pussyfooted around” for too long about intervening to back it and that people died as a result.

O’Brien singles out Australia’s Iraq engagement for particularly scathing criticism, having compared the public statements Howard and senior ministers made at the time with the truths that have emerged since.

On this and other issues, the winner of six Walkley awards for excellence in journalism concludes: “I do think that the picture that was presented to the Australian people was not entirely an honest picture by any means.”

During the 2001 so-called “children overboard” affair, Howard maintained that he was never informed that his ministers’ mid-election-campaign claims of asylum seekers throwing children

off a boat into the water were false.

O’Brien quotes Howard as having said: “Well, Kerry, I can only answer truthfully for myself. If I’m not told something, I’m not lying to the Australian people if I maintain a position that I remain in ignorance that some contrary advice has been given.”

Of that, O’Brien says: “It’s almost like an echo of the three wise monkeys, you know? Hear no evil, see no evil, therefore there is no evil.”

The veteran journalist is equally critical of Howard’s refusal to condemn Pauline Hanson’s attacks on Asians and Indigenous Australians.

“He did not directly disagree with her at all,” he says. “He was trying to have his cake and eat it. He was trying to still appeal to those people who might have been attracted to her by talking to his dislike of political correctness and by saying, ‘She has a right to say these things.’ ”

Every major party leader since Howard took office comes in for criticism to varying degrees in O’Brien’s memoir – Kevin Rudd for failing to act on climate change as promised, Julia Gillard for lining up with “factional hacks” to overthrow a still relatively popular first-term prime minister, Tony Abbott for out-of-touch flip-flopping and Malcolm Turnbull for having a political tin ear.

O’Brien details some of their achievements, too, insisting the bouquets would have been more plentiful had he been writing about any of the issues or leaders as a standalone exercise.

Of the current prime minister, Scott Morrison, he observes to The Saturday Paper: “He has shown no indication that he can break the recent mould of leadership in this country.”

And O’Brien is particularly critical of Opposition Leader Bill Shorten.

He describes Shorten as a “mystery” who appears to lack conviction or passion in public.

“Most political observers are virtually assuming that Labor is going to win the next election.” O’Brien says. “The only question mark over that outcome is that Shorten has absolutely failed to capture the imagination of the Australian public. And in opinion poll after opinion poll, the public is reflecting the view that he is not a convincing leader.”

But he credits Shorten and Labor with breaking from the “timidity in politics” in shaping their tax policy on negative gearing.

On journalism, O’Brien laments the loss of respect for wise elders who “carried the history in their heads” and understood how power is wielded.

“I think history is too easily forgotten and that worries me,” he says, noting newsrooms are getting younger and younger.

While acknowledging the skills and accomplishment of many younger journalists, he says: “We learn as we grow older that life is much more complicated than we possibly saw it when we were 20 or 25 or even 30 … We come to understand that things are not black and white, that there really are shades of grey … [that] should be part of the picture that we paint, and we write.”

O’Brien proffers his own ideas for addressing some of Australia’s political problems.

On asylum seekers, he proposes that Gareth Evans and Julie Bishop – both former foreign ministers who understand politics and have good contacts internationally – be commissioned to consult regional neighbours and devise an alternative to the offshore detention system.

And he says there should be a royal commission into the future of work – along the lines of the Whitlam government’s royal commission into human relations – to address the urgent challenge technological change poses to job opportunities and the structure of society.

O’Brien’s book, to be published on November 14, also reveals the journey he has been on. Researching convict ancestors led him to difficult suspected truths about their encounters with Indigenous Australians. For him, the whole issue of Indigenous history has become an insistently ringing bell.

So how will the ginger-haired man the right-wing commentators dubbed “Red Kerry” answer those who might suggest his memoir merely proves their suspicions about him?

“I would argue that I did keep my own personal political views under control – or in the privacy of my own head – as I was going about my work as a journalist,” O’Brien says.

“And I am now no longer in that same environment. How can I write an honest memoir that does not offer some reflection on the things that I care about?”

Replying to those who have asked or wondered about his distinctive red hair, the former television presenter insists he has never dyed it and it’s not a wig.

Although it’s the women in politics and on television who most frequently are subjected to commentary on their appearance, his assurances are a reminder that men cop it too.

At least that’s one thing Kerry O’Brien and John Howard have in common.