The economist Vicky Pryce is talking quickly, stopping only to take a bite out of a croissant she has stuffed into her bag on the train from London.
“I got this on the train. I don’t like waste,” she says, finishing it off before she scrunches up the paper bag and puts it back in her handbag.
It is the most brief pause before she turns back to me, her wide eyes magnified behind her thick glasses, and says: “Prison doesn’t do what it’s supposed to do; it doesn’t stop crime or reoffending. So why are we putting people in there?”
It is a question she has come to ask after her own short stint in jail for perverting the course of justice, following the revelation that she had accepted her former husband and MP Chris Huhne’s speeding points - a scandal which prompted his resignation.
A nine-week spell in prison was her punishment for the historic offence, and she vowed to document her time in jail in a book. But after seeing the reality of life in prison for women, she is now posing the question of why we put women in jail to the political establishment, journalists and experts in the field - many of whom have been gathering to discuss the issue at Northumbria University.
“I thought I was going to document what was going on, but I had no idea who I would meet,” she explains. “My attitude to everything changed because of how vulnerable these women were. They came to me and their stories were astonishing. They were very keen that I should go out and talk about it because they haven’t got a voice.”
Rattling off statistic after statistic while calling herself a “nerd” for data, she explains that she learned how many women behind bars had been emotionally, physically or sexually abused, while just under half had no qualifications to their names.
“I had no idea about this,” she says. “I didn’t know anyone who had been to prison. They were surprised I had come out of my cell. Of course I was going to come out and see them.
“Then we all sat on a bench and everything happened and I got all these stories. The most important thing for me was to be able to use that and put it with the data I got from the outside to see what that really means.”
What that truly means, she maintains, is that prison is an expensive strategy that is no longer working for women - a view confirmed by experts during a round-table discussion at the university. Data suggests that the women’s population in prison doubled between 1995 and 2010, while only 17% of women entering prison in 2013 committed violent offences.
But once inside, they make up for almost a third of all self-harm incidents, despite comprising just 5% of the UK’s jail population.
And their crimes? Just over 20,000 women were in prison in 2012 for theft compared with only 3,582 who were behind bars for violent offences. Yet their punishments tend to be short jail sentences that offer no scope for rehabilitation, alongside separation from their children, who are often taken into care at an annual cost to the taxpayer of £50,000 for each child.
All of this, argues Pryce in her new book Prisonomics, fails to help female prisoners turn their lives around and is also an economic disaster. Reoffending alone costs the UK economy £9.5bn a year, she says.
“A third of the women who go to prison already have children and are single parents,” she continues. “You could see them being thoroughly depressed that they had no control over the children because they were in care. That costs on average £50,000 per year, in addition to the prison. That is a very expensive thing.”
Louise Ridley, a senior lecturer in criminology at Northumbria University, agrees.
She said prison was no longer suitable for women unless they posed a serious threat to public safety.
“We lack imagination,” she says. “If you look at countries like Sweden, they are much more imaginative with what they do with women offenders.
“We need to think, ‘Do I need to be protected from that person?’ Nine times out of 10 the answer is no. If we don’t need to be protected we don’t need to spend the money on putting them away.”
She continues that the solution lies in community-based punishments, which would allow women to stay with their families and seek help for the reasons behind their low-level offences: drugs, poverty, abusive relationships are all often catalysts.
And though Pryce is well aware her short stint in jail and its aftermath are far less traumatic than the circumstances facing her fellow female prisoners - who might not be lucky enough to be offered a publishing deal upon their release - many women who have come out of jail are also of the view that something needs to change.
Among them is Paula Harriott, who spent four years behind bars after she was caught with 750g of cocaine.
Now working for offender charity User Voice, Paula, who battled a cocaine addiction for 25 years, has turned her life around to help others who have spent time in jail.
But there is one part of her previous life in crime that still sticks: her broken relationship with her children.
“The experience of prison in and of itself was traumatic because I’m the mother of five children,” she says. “You look around and see the actual mess you have made of your life. You’ve been punished by the courts, but you start to self-punish as well. That’s why a lot of women in prison start to self-harm.”
The 56-year-old said she felt there had to be another way.
“If you’re in jail what are you? You’re nothing,” she says. “I was MF4865. They give people prison numbers for that reason. It drives home that experience. Some women can’t recover from that. In that way prison doesn’t work for them.”
She admits she was lucky, in a way, to be in prison for four years as she was able to take advantage of the services which helped her to get clean of cocaine, and attain counselling after years of an abusive relationship. But she said longer sentences were in no way an adequate enough solution for helping women in the justice system.
“I was in prison long enough to benefit,” she says.
“It’s not an argument for longer sentences but you need a lot of interventions in place to enable people to recover.”
For Pryce, now a patron of the charity Working Chance, the solution to all of this is clear-cut: education and jobs.
In jail, 40% of offenders cannot read or write, she adds.
“There is evidence to suggest that the current system is not fit for purpose,” she says. “But what really matters in practical terms is education and employment. The first job I was offered was for Working Chance. It is jobs that make the greatest difference.
“Why should you go on having this thing over your head if you’ve been to jail? The chances of an ex-offender who has a job reoffending is less because they have a job They want to keep their job. And that, in my view, is the most important thing that can happen.”