Martina Cole kicks off Harrogate 2011

Martina Cole was on ebullient form first thing in the morning on the opening day of the Theakstons Harrogate International Crime Writing Festival.

Interviewed by festival chair Dreda Say Mitchell, Martina Cole arrived saying that she had toyed with the idea of "doing a Britney" with her interviewer as she got up on stage – instead she showed the large audience how much she cares about the hard-luck people who figure in her novels, as well as encouraging those who would seek to follow her success.

In talking about her early years, Cole presented herself as someone who persisted in the face of likely failure. Having been told by her schoolteacher she would never amount to anything, the young Cole replied: "It could be worse, I could be teaching in a shit school like this." She added that she next expected to achieve anything – "I used to lay in bed listening to the radio, dreaming of being a writer, but I never thought it would actually happen." She now has 19 acclaimed bestsellers to her name.

She wrote her first novel, Dangerous Lady, at the age of 21, seeking to overturn the then ubiquitous image of women in crime novels as glamorous sex objects. "I wanted to put women in the real world," she said. But she didn't have the self-confidence to do anything with her novel until nine years later, when she was clearing out a cupboard and read the manuscript again. She "sat down with a glass of wine and a cigarette – no change there then… and I thought it was better than the number one crime novel in the charts." She talked about her close relationship with her agent and her publishers, but admitted that she was still "sick to my stomach" with nerves before the event.

What came across strongly was how much Cole cares about young offenders, and girls in particular. She talked extensively about both the gang crime that inspires her work and her own experience of young offenders, especially girls who have found themselves in prison and separated from families. "We have a big underclass, whatever the government say," said Cole. She added that "women can be more aggressive than men, men just do it fast. Men get mad; women get even."

The author's work with prisons has been well documented – "about eight or nine years ago, The Guardian found out I'd been going to prisons for ten years, and suddenly I was chic" – but she still believes that "the majority of prisons are shit." The result of imprisoning young women, she told Mitchell, is a breakdown of the family. "Women end up with psychiatric problems because statistically they get longer sentences – when men go to prison, the person they trust with their children is the mum; when women go in, the dad usually isn't around, so there's no one to look after their kids, so they [the mothers] end up with mental problems. If they don't have mental health problems when they go in, they do when they come out… I'm not saying we shouldn't put women in prison, but we need a way of keeping families together."

Ending the event with an audience Q&A, Cole presented her home life as half chaotic, half everyday. She described her writing routine as starting at 10pm and going on until her chickens – who she calls 'The Girls' – start crowing. Many of her stories included her TV viewing habits: Come Dine with Me is a particular favourite, including as it does both food and "idiots". She's even behind a short film, Mrs Peppercorn's Magical Reading Room. But if readers are worrying that the queen of crime has gone soft, she explains she is happy to spend so much time with her characters because: "If I don't like them any more, I can kill them."

Martina Cole's new novel is The Family.