It has been a punishing period for the former head of Liberty, after her report on antisemitism in Labour was called a ‘whitewash’. Was it mistake to follow this by accepting a peerage from Corbyn?

Shami Chakrabarti seems smaller than I remember. We have met a couple of times in the past, but I had never noticed until now how petite she is. The barrister was just 34 when she took charge of the human rights organisation Liberty, and, 14 years on, still looks like a thirtysomething, but the bombastic stature she used to project has gone. Having joined the Labour party last May, the shadow attorney general looks almost fragile.

“I’m not a natural combatant,” Chakrabarti acknowledges softly. “I’m actually not a very fighty person.”

On her career as a human rights campaigner, she reflects: “Even if you’re controversial, you’re not party political, and that brings a certain protection in British liberal democracy. Then the question, I suppose, is why would you chose to give up that protection at one of the bitterest moments in British politics, during that odious referendum campaign, when some really nasty stuff started bubbling to the surface? I don’t go around trying to pick fights with people. But sometimes somebody else picks the fight, and you have to pick a side. And I picked a side. I don’t think I could have lived with myself if I didn’t try to do my bit in one of the most bitter and divisive moments.”

To describe last year as uncomfortable for Chakrabarti would be an understatement. Her investigation into allegations of antisemitism within Labour ended with a report condemned by many as a whitewash. Her appointment by Jeremy Corbyn to the House of Lords weeks later compromised its author’s integrity even further in the eyes of many more. The revelation that she sends her son to Dulwich College, an exclusive private school, led the New Statesman to conclude: “It’s difficult to recall a time when a liberal icon has fallen so far, so fast.”

Now she has written Of Women, an analysis of global gender inequality so irreproachably blameless that I half wondered whether that was its chief appeal for Chakrabarti. After the bruising legacy of last year’s rows, who could blame her for choosing a subject that offered a safe return to liberal terra firma? But she says no, a book about feminism “was coming for some time”.

Chakrabarti almost shudders at the word memoir – “That wouldn’t be for me, it’s not in my DNA” – and Of Women is instead a careful, fact-based appraisal of enduring gender inequalities. “This is not a memoir, but I think if you’re asking me personally why – what my 15-year-old son has charmingly called ‘my crappy feminist book’ – why now, I think it’s partly middle age. And I think it’s partly the loss of my mother [in 2011]. There wasn’t ever the time for me to say thank you properly to her, or for me to really acknowledge not just on a personal level, but in a bigger political way, what she had been up against.”

Solidly researched and well-furnished with statistics, Of Women is a defiant reassertion of evidence in a post-truth age. “I think evidence and argument do change people’s minds. I don’t think it’s all post-fact now. I think we are creatures of logic and emotion, and some of the facts are pretty devastating. And I would challenge somebody not to be moved emotionally as well as logically. It’s symptomatic of us being bottom of the pile. This affects rich women, poor women, black women, white women, women in the first world, women in the developing world. I call it an apartheid – and I do not use the term lightly.”

She grew up in suburban north London, and, recalling being the daughter of working-class Bengali immigrants and studying law at the London School of Economics, says: “I think I was unaware to a large extent of my race and sex. You have to get a little bit older to get a little bit of perspective.” As an in-house lawyer at the Home Office in her 20s, she began to notice the way older female colleagues were spoken of and treated. “And I think it would be naive to say that I haven’t had some stick for being a woman. And being a black, political woman is a triple whammy.”

Nothing in Theresa May’s race report this week surprised her. “That doesn’t mean to say it wasn’t a good thing to do. However, instincts and good intentions are just not enough. This is why I’ve written my book at this time, when society is so unequal. You can’t just tackle inequality by all just agreeing not to actively discriminate; you have to go further than just publishing the information.”

What did she make of a letter to the Times from several high-profile BAME names, warning against the “misuse” of statistics to falsely cast minorities as “victims of racism”? She sighs, wearily. “We can tell ourselves that everything is fine if it makes us feel better. But it doesn’t make the world better. It’s like these old white guys in the Labour party saying: ‘I’ve never seen bad behaviour in the Labour party in 150 years.’ Well, of course you haven’t, mate. But that’s just what you see or don’t see. That’s the evidence of your sense, not mine.”

Chakrabarti has seen enough misogynistic abuse online to no longer look at social media until it has been filtered by her assistant, and she wants to see action taken. “People would not get away with this kind of harassment and abuse on the public street. Why are they getting away with it online? So, proposition No 1: let’s resource the sensible policing of the online world.” If anything, she goes on, social media platforms are less like a public street than a bar, “where standards should be even higher. So I also think there’s an opportunity for consumer action to say: ‘We don’t want to use your bar if your bar is not a safe place to be. We’ll go to a different bar that’s opening up down the road that is a more convivial environment.’”

Facebook Twitter Pinterest With Jeremy Corbyn at this year’s Labour party conference. Photograph: A Davidson/SHM/REX/Shutterstock

Some of the worst online misogyny, I point out, has come from voices on the left. She pauses carefully before answering. “I think that, actually, in recent times, less so. Jeremy Corbyn himself is a very gentle human being and treats women with a great deal of respect, and so I don’t think he’s leading a macho culture … I think it is everywhere, but I think we’re understandably more upset by any hypocrisy coming from people who are supposed to be for the cause of equality. And there’s always the danger of, ‘I’m on the side of right, therefore I don’t have to self-criticise.’ I think we all need to be self-critical.”

Is it just a coincidence that Labour hasn’t produced a female leader, let alone a prime minister, while the Tories have given us two? “I don’t know. Look, it’s not a source of great pride, and it’s too late to be coy about this. As far as I’m concerned, next time it’s a woman. My very strong preference is that the Labour party should say to itself, ‘It’s time we had a woman after Corbyn.’”

But when I ask by what mechanism that would be achieved, she quickly qualifies the comment. She doesn’t mean the party should allow only female leadership candidates next time, nor legislate to alternate the gender of its leader. She would, however, consider a constitutional rule change whereby the deputy could not be the same gender as the leader. “Or the party could have two deputies, one of either sex. There are different ways of doing it.”

Chakrabarti can be surprisingly reluctant to commit to an opinion, and often sounds more like the Home Office civil servant she once was than the firebrand human rights activist we came to know at Liberty. Although deeply unhappy about privately run prisons, she won’t say if she would like a Labour government to take them into public ownership. “It’s not for me to unilaterally make a policy in an interview with you, but I think it’s certainly something to be looked at.” In Of Women, she sounds very enthusiastic about a universal basic income, and tells me: “I think it’s something we need to look at.” But when I ask if she has so much as discussed the idea with Corbyn or cabinet colleagues, she immediately closes down. “If I had, I wouldn’t tell you.”

She isn’t entirely noncommittal. The Sun once branded her “the most dangerous woman in Britain”, and when asked last February to name the most dangerous person in the country, she nominated David Cameron. So who now? “Well, goodness me, so many potential candidates,” she laughs. “But today? Maybe Boris Johnson. I’m not just sending sisterly solidarity to Theresa May in her difficult moment. He allegedly represents Britain on a world stage, and the world is quite dangerous right now, so to think that the advocate for world peace from Britain on the world stage – the person who we might ask to intercede on our behalf with Donald Trump and North Korea – would be Johnson is a pretty terrifying prospect.”

I am curious to know how it felt to go from being the lifelong darling of the liberal left last year to finding herself suddenly accused of … “Horrible things,” she completes my sentence. “Corruption and antisemitism. But proposition No 1, I don’t believe I was such a darling. The whole hero-to-zero narrative is a very good trick, so I think we need to be a little bit careful. I can remember at the height of the ‘war on terror’ going to lovely little leftwing dinner parties, and friends saying, ‘Stop having a pop. What do you want? The Tories back in power?’”

Membership Event: The fight against gender injustice with Shami Chakrabarti

But even when at odds with Labour policy, she had always occupied what was widely regarded as the moral high ground. When she accepted a peerage weeks after delivering a hugely helpful report to Corbyn, what dismayed so many of her longstanding admirers was the impression that she had vacated it. What was the experience of this sudden opprobrium like for her?

“I treat those two impostors just the same.” But her eyes are becoming glassy and her expression suggests otherwise. “That doesn’t mean,” she adds quietly, a moment later, “I’m not human, or that it’s not horrible to have people say horrible things about you. Everyone’s got feelings.”

Had she not foreseen how her appointment to the Lords would look? She hesitates. “I think that if you drive into a war zone, you’re going to get shot at, even if you think you’re driving an ambulance.”

Of Women by Shami Chakrabarti is published by Allen Lane (£20). To order a copy for £14.60 go to bookshop.theguardian.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min p&p of £1.99