There is a photograph of Jo Brand as, I would guess, a nine year-old, wearing a floral dress and looking slim and pretty. No, more than pretty. With a plait of hair over one shoulder and, with her big eyes and big smile, she looks adorable. It is reproduced in her new memoir, Look Back in Hunger, and the caption reads: ‘Yes, I was a nice little girl once.’ How poignant is that?

She is 52 now, with a long and successful career in comedy behind her. She has, indeed, a valid ticket to ride on the celebrity memoir gravy train, which has seats still warm from Paul O’Grady, Dawn French and Julie Walters, the top three best-sellers of last Christmas.

But her motivation, you suspect, was more than mere avarice. She wanted to work out for herself how she went from being that adorable child to her first incarnation in the mid-Eighties: The Sea Monster, as her act was called, a Doc Marten-wearing, spiky-haired, overweight, alternative comedian who, with her aggressive, scatological, gynaecological and, generally, feminist comedy, delivered in a bored monotone, scared the bejesus out of a generation of men.

It was often assumed that she was a man-hating lesbian, an assumption she did nothing to dispel (despite being a man-loving heterosexual). For the record, she is married to Bernie Bourke, a psychiatric nurse, and they have two young daughters.

She became a mother at 43 and was funny on the subject. ‘They say men can never understand the pain of childbirth. Well, they can if you hit them in the testicles with a cricket bat for 14 hours.’

The impression I get, as we sip coffee on a rainy morning in the bar of the British Film Institute, is that it really was all an act. In person there is a gentleness to her which takes you by surprise. And the impression you get from her memoir is that her defining characteristic was, and probably still is, kindness. After all, for almost a decade she worked as a psychiatric nurse herself.

‘It’s such a stressful job you shouldn’t do it all your life,’ she says in her lugubrious, slightly nasal voice. ‘After a certain amount of time you become blunted to people’s needs, or cynical, or in some cases rather sadistic. People do snap and they’re the ones who make bad nurses.

‘You need patience and empathy. Sometimes you only need to give the illusion of control, because if someone is waving a machete, as happened to me once, the worst thing you can do is be a weak, heap of begging, because that feeds into their feelings of being out of control. They behave worse if they feel they’ve created chaos.’

Because they sometimes seemed so happy when they were in the manic, or ‘up’ phase of their illness, Brand used to feel strangely envious of her bipolar patients. ‘They do all those things that you would quite like to do yourself but you don’t because you lose your nerve.’

Such as? ‘They react to every impulse. If they want to throw their house keys off Waterloo Bridge they do it. But however strange their behaviour, a good nurse has to always remember that her patients are still paid up members of the human race.’

She sips her coffee. ‘You just have to see through the abuse – and sometimes the smell – and treat them with respect. What matters is not degrees in psychiatry but whether you are a warm human being who wants to help people who are suffering.’

As it happens, Brand did also have a degree, in social sciences. And in recent months she has been able to put her experiences of working for the NHS to good comedic use, co-writing and starring in Getting On, a darkly satirical, three-part drama series for BBC4 about life on a geriatric ward. It does for the medical profession what The Thick of It did for politics (and it is no coincidence that Peter Capaldi directs it). A further six series have now been commissioned, and yay to that.

As for Brand’s empathy with her patients, she thinks that may have had something to do with her family background. Though her father, a structural engineer, was not diagnosed at the time, he was a depressive, one who would fly into uncontrollable rages.

‘At the time I just thought he was a grumpy old sod. Whatever situation you are in, that is what is normal for you.’ At one point, when she was 16, this anger led to her father piling up all her clothes and burning them. Is her father embarrassed by the portrait of him in her autobiography?

‘Not really. I think he would have been 40 years ago because there was more stigma about depression then. At the time I wasn’t aware of how ill he was, so I thought he was just being sadistic and nasty. You try and protect yourself as best you can. I would just lie about what I was up to with my friends and so on. I got away with it most of the time.’

If there was a moment when the girl in the photograph began to transform herself into the Sea Monster of her early stand-up career it was when, after her O-levels, she was taken out of the grammar school in Tunbridge Wells that she loved and sent to a sixth form in Hastings that she hated. It was a huge upheaval that left a core anger.

‘I knew at the time I was angry. At my new school I deliberately picked bad girls as my friends. Skivers. We played truant most days. I suppose I was punishing my parents by harming my own prospects.’

Things became so bad, she was kicked out of the family home. She went to live with her boyfriend, a ‘posh’ junkie four years older than her: ‘I thought Dave was the most magnificent person to fall in love with because you don’t want a conventional nine-to-fiver at that age. Wild men are so enormously attractive. He was Heathcliff. Mr Rochester. He was enormously bright and unpredictable and funny.

‘Other people thought he was a knobhead and I quite liked that about him as well. He never did heroin in front of me so he was being slightly responsible in that sense. But we did smoke joints and do LSD.’

So she never tried heroin?

‘I have tried heroin, but it wasn’t what I was looking for.’ What happened next gave her one of her most memorable stand-up lines. ‘I went on the pill when I was 16, put on four stone… so that proved to be a very effective contraceptive.’

Actually, she says now, it was three stone in six months, which must have been a huge blow to her confidence. But there is no denying that the subject gave her some funny material.

Her early stand-up routines would begin with her putting her mic stand to one side, so the audience could see her. She would then say something like: ‘I must be an anorexic because an anorexic looks in the mirror and sees a fat person.’ Or: ‘I was the child who was asked to play Bethlehem in the school nativity play.’

The jokes made audiences laugh, but did they also give them permission to bully her? ‘I didn’t see it that way. If anything, it was a shield. I was saying: I know I’m fat but I’m funnier on the subject than you will ever be, so why bother heckling me about it.’

As a child she was always told by her parents to think of the starving Africans and ‘finish her plate’, and she thinks that may have had something to do with her attitude to eating. Certainly, she doesn’t tell her own children to finish their plates.

‘I’m not a flag waver for obesity,’ she says. ‘It’s not healthy and you have a crap life because there is such a downer on it.’ I ask what effect her dramatic weight gain had on her psyche. She did, after all, find herself drawn to that which should have frightened her; you don’t need to be told by a heckler, as she was at her first gig, to ‘F— off, you fat cow’.

‘Yes, but it wasn’t as if I had never had comments about my weight. And I also felt that no one in an audience could abuse me worse than the sort of abuse I had had at work as a psychiatric nurse. People in a manic phase of bipolar are enormously eloquent and their abuse is focused and personal and raw.

‘So to go on stage and have someone shout “F— off, you fat cow” was almost a pleasure. A lot of them were just showing off in front of their mates. But sometimes I would get heckled and I could tell there was real hatred in it. I don’t know what that was about, perhaps common-or-garden misogyny.’

Brand believes crowds can take on an aggressive mob identity and become sadistic. ‘You get a sense of what the Coliseum in Rome must have been like. If the atmosphere turns against you they go for the kill. Usually though, an audience has booked to see you and that is fine.

‘But sometimes I will do a corporate gig where it isn’t me they have come to see and you will sense there is a sigh of despair when I come on. Then it becomes a challenge and it really feels like a victory when you get them laughing despite themselves. I like the purity of stand-up because it is all about whether people laugh at your jokes. Either they laugh or they don’t.’

Sometimes, when they didn’t, she would come off stage and cry.

‘Yes, the dressing room can be the loneliest place in the world when you have just died on stage.’ She shakes her head. ‘No, actually, the loneliest place can be in the car afterwards, when you are sharing a lift home to London from Manchester, say, with three other comics who stormed it while you died. They are embarrassed on your behalf. The etiquette is that no one mentions it.’

And here is another paradox, one that reveals a pattern in her life. Jo Brand was the aggressive feminist who turned out to be kind and gentle in person. She was the passive, self-sabotaging person who hoped to find lasting love from boyfriends who were incapable of being faithful to her (she split up with Dave after he cheated on her).

But her most contrary act was to try to get whole audiences to love her, as a form of self affirmation, of filling the emotional void left by her parents. She did this even though she knew they would attack her, and she would have to attack them, at least at first.

We seem to be in the realm of sado-masochism here. ‘Well, the more scary the gig,’ she says, ‘the greater the satisfaction if it works. And I did want to be liked by an audience. Feminism was not a fashionable school of comedy. I wanted people who hated feminists to realise we could laugh at ourselves, and be funny as well as serious and boring.

‘A lot of men after gigs will come up to me and say: “You were quite funny.” They never go: “You were very funny.” But quite funny is the ultimate praise from a bloke who would originally have hated me. I was happy to settle for grudging respect, I suppose.’

I ask her why she played up to the tabloid assumption that she was a lesbian.

‘Well, in terms of my dress sense I would have looked like that anyway if I was going out. But the whole black, baggy top and trousers look was because I knew a lot of women comics who would dress up in a glamorous way for a gig and that became a huge focus for the male elements of the audience. I would rather have men shout: “F— off, you fat lesbian” at me than “Get your t— out”. Men used to say the most awful things to attractive female comics.’

Did she enjoy the thought that some men were scared of her? ‘Yeah, I rather revelled in that. I had garnered a reputation for chewing up and spitting out hecklers and that served me well. But actually the toughness was all front.’ She is afraid of heights and the dark, she adds. And there is a vulnerable side to her which the public doesn’t see.

‘But I don’t cry easily and I deliberately don’t cry when people want me to, for documentary programmes and so on. Like when I did my Vera Brittain documentary and we visited her grave. It was p—— down and the crew were clearly hoping I would cry, like they always do on these programmes. But I think crying on those occasions, in an exhibitionist way on television, reduces the value of the emotion.

‘Crying should be a private thing. Of course I do cry from time to time, but I would never want to have an audience for it.’