Campaigner and Oxford Brookes Chancellor Shami Chakrabarti on her new book 'On Liberty'

If David and Goliath had been a modern-day fable, David would have been a woman with short dark hair, black-kohled eyes and a dark trouser suit.

Goliath would have represented governments, the legal system, politicians, Question Time panellists, politicians, news teams and TV crews. And every time David climbed into the ring, Goliath would have winced and closed his eyes, knowing there was a long, bloody and relentless battle ahead that he could easily lose.

Yes, Shami Chakrabarti is a force to be reckoned with, as various Home Secretaries can vouch for, jumping into the public arena on a daily basis without batting an eyelid. Nothing fazes her.

But getting her to talk about herself is nigh on impossible. As a former lawyer, she’s brilliant at deflecting questions, albeit in a charming manner. Unwilling to venture into her private life, neither does she consider herself an individual, but rather a sum of her Liberty parts.

I beg to differ. Even while reading her intense, unrelenting and impressive fight for human rights in this country, as chronicled in her new book On Liberty, her personal contribution and journey shines through. Yes she’s in the right job and yes she’s surrounded by equally passionate people with a similar belief in justice and civil liberties. But that she is a indefatigable campaigner, personality and inspiration in her own right, and one who’ll go down in the history books, is indisputable. Shami Chakrabarti is a woman to be reckoned with.

In the end I have to resort to brute force, pinning her down mercilessly, making her reflect on her own part in her success. “What me?” she says, lost for words for the first time during our interview. She stutters before finally coming up with “My motto is ‘everyone is equal and no one is superior’,” which doesn’t answer my question in any way, shape or form but is a charming insight into a woman who has devoted her life to campaigning for others, whether you agree with her point of view or not.

“I am a Marmite person, I know that,” she says. “I incite strong reactions, but that’s alright, I don’t mind because we have to have these debates, and these points of view need to be got across and explained in a democracy, even when we roll the stone up a hill and then watch it roll down again. It doesn’t feel like a wasted life and that’s good enough for me. That’s what matters.”

Looking back at her campaigns from the 42 day detention rule, to the War on Terror, slavery, ID cards, refugees, surveillance, Legal Aid, the list goes on, and you’ll see that Shami’s had her work cut out for her.

But let’s go back to the beginning. Because although we all know Shami as a fearless campaigner, director of Liberty, former Home Office lawyer, Chancellor of Oxford Brookes University and a constant thorn in the side of ‘the Establishment’, she’s also a modern day success story Cameron’s Big Society would be proud of.

A North London state school pupil whose parents came here from Calcutta and saved up to make sure their daughter got every advantage in life, she was top of the class, progressed quickly to LSE, the Home Office and then Liberty, first as In-House Counsel, then as Director, where aged 45 she still resides.

I remind her that seven years ago she said her role at Liberty was a finite one, because as the face of the charity, she had become their ‘human logo’. “And look here I still am,” She laughs, “thanks for reminding me of that. But I’m still so passionate about what I do. I love my job and new things unfold all the time,” she says utterly unapologetically. “But then if I wasn't doing this, I’d be sitting in the pub complaining about the same things. So while it’s a way of life, it’s a privilege to do work that you love and care about.”

Shami Chakrabarti on the campaign trail

As for Shami’s influences and inspiration, there was her father’s famous lecture about capital punishment firing her up as a child, her mother ”she was an amazing woman, denied opportunities, so I owe it to her,” and the birth of her own son, who made Shami believe she could achieve anything, and induced an empathy in fellow humanity she’d never felt before.

But more than that, her fearlessness is what makes Shami stand apart. “My parents taught me that I could achieve anything. So if I have to go on TV, or to a ministerial meeting, or battle it out on Question Time, I put my Liberty jacket on and I don’t worry. I may have moderated my behaviour over the years through experience and age but I am as passionate now as I ever was about what we do. I’m a human rights campaigner. I never wanted to be a movie or rock star. I like a challenge but more than that I want to connect with people.

“So I’m very lucky. ‘I’m a middle-class mother who isn’t struggling to pay the bills. I’m not clocking in and out to put food on the table doing two jobs. So if I have to work at weekends sometimes to respond to something, that’s fine because I still get to my son’s football matches during the week. Everyone has a demanding life.”

I wondered whether taking on the Chancellorship at Brookes was a way of testing the water in another profession, putting out feelers if you like. “No, being Chancellor is like being the university’s mascot or cheerleader and works very well with my work at Liberty because it brings me into contact with young people, students and academics, so I really enjoy it. It’s life enhancing stuff.”

She laughs remembering the call she took from the previous Chancellor Jon Snow suggesting that she take on the role. “I thought it was a hoax call. There were lots of practical jokes going on at the time at work,” she explains.

And then she squeals uncharacteristically and adds: “Not as bad as the call from Danny Boyle asking if I’d take part in the Olympics 2012. I was so sure that was a hoax call I made sarcastic comments all the way through the call and had even decided which of my colleagues was winding me up because he had the same West country accent. After a few minutes Danny got a bit hurt and said: ‘Well Doreen Lawrence has said she’ll do it.”

“But I can’t just change tack and go and save the whales instead. This is a vocation. I’m a human rights campaigner.”

And author I remind her. “I’ve tried to make it Liberty’s story, written like a spoken voice with cases and anecdotes. The critics say On Liberty is not personal enough, but it’s not a kiss and tell, and my work is very personal to me.”

Ask whether her book tour has made her more approachable she replies: “Am I more amenable? Yes if the little part of me you have seen on TV is very hard-edged or trying to get a hard-hitting message across in a two minute news bulletin, talking about something pretty awful like torture, yes this has more nuance, humour and humanity.

Perhaps they come to see the real Shami? “What is the real me?” she ripostes. “I’m just trying to reach people and do it with a sense of humour.”

And then she recounts an anecdote made during a talk in Bristol about the War on Terror. “At the end a young woman got up and said ‘Martin Luther King never said ‘I had a nightmare’. I’ll always remember that piece of advice. You have to tell people about bad stuff and abuses but you also have to motivate them to do something about it and leave them with a bit of hope.

“Because ultimately I’m an optimist, otherwise how could I do what I do? Sure we all have good and bad days. The issues I have to talk about aren’t exactly Great British Bake Off, but I believe in human beings, and I have always I seen the law as a potential agent for change.”

Blackwell's Oxford Presents: Shami Chakrabarti - 'On Liberty' at Lady Margaret Hall on Wednesday, November 26. 01865 333623 or email: events.oxford@blackwell.co.uk