“Linda”, a woman in her 50s, has an appointment with Amanda Brown, a prison doctor at HMP Bronzefield in Ashford, Surrey, since 2016. Linda is inside because she tried to cut off her then husband’s penis with barbed wire. “I didn’t manage to finish the job, sadly,” she says. Married for 28 years, she adds: “The day I came here was the day I got my life back.”

In The Prison Doctor: Women Inside, Brown details how Linda’s ex-husband controlled every second of her existence, undermined her constantly and spent hundreds of pounds on prostitutes. Linda, isolated from family and friends, had become the classic victim of coercive control, punishable since 2015 by up to five years in jail. When she finally snapped, she lost her liberty but regained some freedom; a not uncommon story in female penal institutions. 

This book, written with Georgina Rodgers, is a speedy follow-up to the bestseller The Prison Doctor, which charted Brown’s move in 2004, after 20 years as a GP, to a young offenders’ institute, then to Wormwood Scrubs, before a move to Bronzefield. 

This second title focuses solely on life in the largest women’s prison in Europe. Holding 527 inmates, it is accurately described by the author as looking like “an ugly leisure centre”. Brown is not the first doctor to write a memoir, as Rachel Clarke’s Dear Life and Atul Gawande’s Being Mortal attest. But where those books feature searing prose, Brown’s style is prosaic. Of her hugely taxing job, she says: “It kept me on my toes.” However, her compassion and commitment shine through.

In one five-hour shift, Brown takes care of up to 15 new arrivals, most with “physical and mental health issues, arriving with bags of different medications… some empty, many of them out of date”.  She captures the constant cacophony as women scream, shout and bash against their cell doors. Two-thirds of the way through the book, she raises the key question. Treating a woman in her late 70s, sentenced for arson with a long history of self-harming and mental illness, Brown writes: “She certainly needed to be in a secure environment, but I really wondered whether prison was the best place for someone with such far-reaching needs.”

As the author points out, while women make up 5% of the prison population (3,297 in May this year), they account for 18% of incidents of self-harming. Eight in 10 are inside for non-violent offences such as shoplifting. The majority receive short sentences, often weeks. They may lose their children, their homes and their jobs, while the addiction, abuse, debt, illiteracy and mental illness that has often been part of their lives since childhood goes unaddressed. “Carol”, on drugs for 27 years since she was 17, is sectioned three days after her release from prison. “It was like my brain had been cracked open and fried like an egg,” she tells Brown.

Half of those who leave Bronzefield have no idea where they will sleep that night. “Shannon”’s “address” in London is under a bridge. She is 26 years old and a so-called “high flyer” – repeatedly in and out of prison. Brown writes that the reoffending rate of those who have 11 or more convictions is 83%. “I’ve got no one and nothing – not even my own teeth,” Shannon tells her.

“Kim”, 33, has self-harmed so much that her body is like “a haphazard drawing of the underground map”. Aged nine, she gave evidence against her stepfather about his repeated rapes and assaults. At 21, a heroin addict, her two sons were taken into care.

Before she worked in prison, Brown says: “My opinion was condensed down into a narrative of good people and bad people… the reality is far more complex.” She recognises that these women with permanently chaotic lives and too little experience of unconditional love can also be “brave, funny… kind”.

Take “Nicole”, for instance, who tells Brown: “I am a basic prison statistic.” She was in care, dropped out of school aged 12, became addicted to crack at 13, then heroin two years later. At 15, she met an abusive older man. She arrived in prison, aged 22, as an addict with two black eyes and weighing six stone. Now she is making something of herself, kicking her drug habit and gaining a qualification in prison in bio-hazard cleaning (“blood, piss, shit and sick”, she explains). Since her release, she has moved into supported accommodation and works as a volunteer supporting women in areas such as domestic violence.

What helps women who repeatedly offend to turn their lives around? Brown visits Anawim in Birmingham and is “blown away”. It is one of 40 women’s centres in the country that untangle the mess triggered by trauma. It costs £65,000 a year to keep a woman in Bronzefield, but women’s centres run on a fraction of that cost. Yet many are on the point of financial collapse. 

“Believe in yourself,” Brown tells a young Romanian, a victim of sex trafficking who has been convicted of drug offences. But, as this book explains, that is an impossible goal for so many women who are repeatedly stuck behind bars.

Yvonne Roberts is an adviser to Women in Prison and a former chair

• The Prison Doctor: Women Inside by Dr Amanda Brown is published by HarperCollins (£8.99). To order a copy go to guardianbookshop.com. Free UK p&p over £15