Journalists quizzing fellow hacks can be an indulgent, tail-eating exercise, but a writer at the top of her game like Lynn Barber more than justifies being interviewed in her own right.

She practically invented the celebrity profile feature, filleting her subjects – often on the strength of a mere hour-long chat – and has won such a truckload of awards it’s hard not to feel self-conscious about my pussyfooting technique and softball questions.

I’m not, as she advises in her latest book, A Curious Career, using a tape recorder, and I tend to talk too much about myself, which is a Barber no-no. Asked by one interviewee if she had children, she said no to avoid being diverted from her task.

I also have poor past form with unco-operative subjects who’ve interviewed for a living – the rudeness of Jonathan Ross, Ruby Wax and Rachel Johnson still burn bright in the memory, but Barber is old-school polite, and if she finds my questions tedious, she keeps it to herself.

Since her 2007 memoir An Education became a hit movie, she’s rather become the story, as well known for her past as the former girlfriend of a conman as for her entertaining and incisive portraits of musicians, artists and actors.

A Curious Career reveals the tricks of her trade; part meticulous research, part Sherlock Holmsian deduction, part Freudian analysis, part Spanish Inquisition.

There are anecdotes of memorable encounters in a five-decade career, and select examples of her must-read interviews, from getting drunk with Shane MacGowan to a bruising, amusing collision with Marianne Faithful and being harangued by Martin Clunes.

She prefers “a monster” to a well-adjusted type, and never cares whether the interviewees like her.

While it would ruin my day to have a run-in with a toweringly rude egotist, Barber would gleefully rub her hands together, “look for signs of fraying at the edges” and prod further at their tender spots.

“If you want to be liked by the person you are interviewing and are going to write only nice things about them, you are not serving the readers. You have got to tell the truth. I am secure enough, I have good friends, I don’t need other people to like me.”

Growing up the only child of slightly odd socially aspirant parents, Barber discovered an innate nosiness and curiosity about the “dynamics of other people’s families and what made people tick”, coupled with a lack of social embarrassment that enabled her to barrel up and ask personal questions.

“Oh, no, I don’t suffer from embarrassment,” she admits.

“It started at school. Everyone would want to know who someone was talking to at the bus stop and would say, ‘You don’t mind asking, you go and ask’. Often I didn’t care, but I was good at asking questions.”

The two-year relationship with a married conman detailed in An Education made her suspicious and convinced of the unknowingness even of those close to you.

“I am endlessly curious about the strangeness and variety of people. There are always new people coming along and it keeps me engaged.”

Liberated

After studying English at Oxford, her career started at Penthouse, where she interviewed fetishists on their kinks, and, memorably, Salvador Dali (who espoused onanism and voyeurism to conserve his creativity).

But it was when she started to write in her own voice that she felt liberated and her career took off, first at the Express and later at The Independent, The Observer and now The Sunday Times.

“It was a feeling I was able to write the truth at last, instead of dishonestly pretending to be omniscient and dispassionate.”

As a “frumpy woman on a frumpy newspaper” (the Express) she took full advantage of her subjects not knowing what to expect from her.

But as her fame grew she earned the nickname Demon Barber, which she quite dislikes.

“I mainly write nice pieces,” she protests. “People tend to forget the ones where you have been charmed by someone and only remember the ones you were hard on.”

These include actors waxing about the trials of the job, people with no self-knowledge (frequently the same) the partners of the famous – “they have to be a someone in their own right” – and PRs who sit in on interviews. “I am resigned to it, but I just ignore them and make sure they are sitting somewhere out of eyeline.”

The interview is the least enjoyable part of the job because she gets nervous that she’s going to “screw up”.

“I’m trying to remember a question that I must not forget to ask or something they’ve already said that I want to come back to, I’m terribly aware of the time ticking, I’m 25 minutes in and I haven’t got anything yet! It is intense and quite tiring.”

Sometimes she’s asked to interview people she’s never heard of, Lady Gaga or Lorde. She says yes, then busily googles to find out why they are interesting.

She believes what makes her pieces compelling is more fundamental than answering hitherto unanswered questions such as why Rafa Nadal fiddles with his underpants.

“All celebrities are people, individuals and I think we are interested in individuals. I hate things that lump people together. I try to get away from stereotypes.”

But why, asked Toby Young after he has been bested by Barber, does anyone agree to be interviewed by her?

“Vanity,” she replies. “The best ones are those who think they will charm me, like Michael O’Leary of Ryanair who was on a charm offensive to be new and lovable instead of foul and Scrooge-like. He thought he could charm me and he most certainly didn’t.”

One who did get under her guard was London Mayor Boris Johnson.

“I’ve done Boris twice and got charmed by him the first time,” she admits.

“All my friends were disappointed that I couldn’t find anything nasty to say about Nigel Farage.

“If you are totally charmed you can’t misrepresent it, you have to say what happened. When I interviewed Rhys Ifans I had a riotous good time with him, but another journalist had a horrendous one and he told her to fuck off. That’s what makes interviews worth reading and writing – they are always different, or should be. You might catch someone on a good or bad day.”

Those she has skewered, she tries to avoid, but giggles that she bumps into Melvyn Bragg (whom she dubbed ‘twitchy, neurotic and vain’) with “wearying regularity”.

“He always shames me by being very friendly.”

She also competitively likes interviewing those who’ve done plenty of interviews so she can get something new.

“It gives me an edge to think of going up against other journalists. I don’t want to deal with people who are naïve about the press, who think that because you seem to be interested in them, you are going to be their best friend. I am passionately interested in a celebrity only for as long as I am writing the article, then I am passionately interested in the next person. It’s the churn of journalism.”

She and husband David Cardiff moved to Highgate in the ’80s where their two daughters went to St Michael’s Primary, then Channing and South Hampstead High.

Memoir

Barber, who likes the trees, urban foxes and “wonderful Waterlow Park”, says An Education was actually a memoir inspired by Cardiff’s early death in 2003 at the age of 59.

“I suddenly started thinking about the past, which I normally never do, as if I needed to write it, in an odd way.

“Reading about dying, I thought that death in fiction and non-fiction normally shows someone fading away and you are having increasingly meaningful conversations, but I wanted to report that it was nothing like that. There were days when he looked as though he was getting better, and days drugged up to the eyeballs when we were not having meaningful conversations but very irritating ones.

“I hadn’t read it as it is, or what it was for me, and I wanted to write about that.”

As for becoming increasingly well known, she says she was “very lucky” that An Education was such a brilliant film.

“Nothing to do with me at all, but it raised my profile, which is fine for a bit, but I get sickened with the sound of my own voice talking about myself.

“Fortunately, work breaks it up. I was recently asked to interview Courtney Love and was glad to take time off from obsessing about myself to get stuck into someone else.”

Lynn Barber is at the LitFest on Saturday at 5pm in discussion with Sue MacGregor.