Let me tell you about this award-winning radio station. It is loved by its listeners, who tune in devotedly. One of its studios is based just around the corner from my home and, as the Observer’s radio critic, I’ve been desperate to hear its output. Unfortunately, I’ve not been able to sample a thing: not its popular rock show, nor its music request programme, its regular sound clash slot, nothing. I can’t enjoy the many delights of NPR, because I’m a free woman. NPR stands for National Prison Radio. Only people in prison can listen.

National Prison Radio only started in 2007, as a single station, Electric Radio in HMP Brixton. It quickly expanded into a national network and now it can be heard in 100 prisons, broadcasting 24 hours a day, seven days a week, to the 85,000 prisoners in England and Wales. The charity that’s behind NPR, the Prison Radio Association, is funded by donations and public funds, but also by its own audio productions. In 2015, it made its first radio drama, Bound, based on real-life child custody cases of babies born to a mother in prison. It has a newish monthly Radio 4 show, Outside In, recorded at the BBC by former prisoners; and it makes varied documentaries, such as Paul Mason’s recent one on social media manipulators.

PRA’s outside output is excellent , but it’s NPR, the sound of the inside, that is the real pull. For while, it seemed as though the only way I’d get to hear it was to become a judge on a radio awards panel. But, after several months of negotiation, the arrangements are in place for me to visit the studio in HMP Brixton.

The prison is situated on a small road, off the main drag out to the south coast. It’s not announced, particularly: you could walk past it – between a tyre shop and a housing estate – and not really know it was there. But it is. There are a few of us on the visit, including Radio 1’s Scott Mills, who’s an ambassador for the PRA. We trot up to the entrance: an office, behind reinforced glass, where we show ID and hand over our mobile phones, keys and other odd items, such as chewing gum (in case it’s used to make an impression of a key). We progress through the prison slowly, in a group, moving between doors that are locked behind us before the one in front is unlocked. The sky seems very far away. Everyone who works in a prison makes jokes, and you know why, when you’re there.

Brixton has a mixed reputation. For many years, it was a Category B prison, just one security level down from the A set-up for those deemed truly dangerous. In 2012, it was changed to a prison for Category C and D prisoners; essentially, those with short sentences for non-violent crimes or those who have served their time and are on their last few months before going back outside. There are some prisoners on ROTL (release on temporary licence: they do voluntary work outside prison) and others are allowed to fraternise outside their cells for as long as 18 hours a day.

The stereotypical prisoner doesn’t exist, you know? The bad guy prisoner. I’ve never met that stereotypical thug John, HMP Brixton inmate

What’s good about Brixton is its several imaginative rehabilitation schemes. There’s Bad Boys bakery, where prisoners learn to make bread and cakes (Bad Boys produce is sold all over London). There’s The Clink, a restaurant where outsiders can book and eat a meal, prepared and served by prisoners. The prison has strong links to Bounce Back, a post-prison service where ex-prisoners learn painting and decorating skills (I’ve used them, I recommend). There is National Prison Radio.

The prison has plenty of problems, however. A 2015 independent report noted that most of its Cat C prisoners have access to “education or purposeful activity for only two or three hours a day”. During 2015, the staffing situation was “desperate”: “inadequate to ensure the humane treatment of prisoners”.

The prison is far from welcoming. The buildings are old and designed for fewer inmates than the 800 housed here. There are cage-style fences everywhere with barbed wire on top. There’s not much ground to walk on. You feel surrounded: everything is oppressively, light-blockingly high. Even the chapel is up some metal stairs, just a darkened room with a stage and a crucifix on the wall. There have been improvements – gym machines in the old outdoors smoking area – but legal highs are rife (“Brixton had the highest level of illegal drug use [of any prison] in the country”, said the report), gang tensions exist and in November last year, a film made with the live video streaming app Periscope showed an inmate being beaten up.

Not a holiday camp, then. Still, the new governor, Giles Mason, is a well-respected progressive reformer, and he’s a strong advocate of prison radio. And here we are at the studios: a plain room, with two small radio broadcast areas and a line of computers around the walls, each manned by a different inmate. The atmosphere is hard-working, but cheerful.

I meet four presenters. Kedia, a laidback Pentecostal believer, hosts Sunday’s gospel show as well as Bob and Beyond, a reggae and soca programme. “Once I’m in here making the shows, I don’t want to go for lunch,” he says. “I get so lost in it all, choosing tracks, editing, mixing.” (Prison radio shows are never live, for obvious reasons. They are checked before they go to air.) I meet Hilary, an ex-inmate and presenter, who has come in especially to talk to me. Then there’s John, in for white-collar crime, who presents two programmes: The Rock Show, on his own, and The Request Show, with Daniel. Before prison, John was a journalist and PR (at one point, he wrote about education) and ran his own company. And Daniel, John’s co-presenter, who says he’s inside because “I was a bad bwoy. And I was.”

I join John and Daniel in the studio for The Request Show. They are very different characters – John: wry, educated, middle-class; Daniel: upfront, upbeat, street smart – but they make good sparring partners. It’s sound clash time, where prisoners send in four tracks, and two different people’s choices are played, each track up against an opposing number. The sound clash is a source of pride, presented as a contest between prisons. Daniel picks one prisoner’s choices, John the other’s, and every time the tracks are played against each other, I choose a winner. Daniel’s prisoner wins. LeAnn Rimes doesn’t stand much chance against Rick Ross, or Skrillex when played next to Kendrick Lamar.

Ex-inmate Hilary, who now presents Outside In for Radio 4. Photograph: Suki Dhanda/The Observer

It's the rollercoaster of emotions, of thoughts, of fears, remembering happy times Hilary, ex-inmate

As ever, when I talk to prisoners (I studied law, and did prison visits for a time), I find them not so different from people I know already. Daniel loves football – he was a youth player for a pro team – and he’s been in prison for quite some time. He found working on the computers tricky when he first started at NPR, because he hadn’t used one in years.

“I haven’t seen any of the people that I was out doing what I was doing with since I’ve been inside,” he says. “Since I’ve been in jail, they ain’t sent me a pound, wrote me a letter, I had one visit in the first month. But I don’t hold grudges. It’s the way. Most prisoners are normal people, people who have made bad decisions, bad choices, got caught up in the wrong place.”

“It’s easy to end up on the other side,” says John.

Before Brixton, John spent 18 months in Wormwood Scrubs, which he found hard, because he couldn’t find like-minded people. “At any one time, there was only one person on the bridge I could really talk to. And I was on the largest wing in Europe.” He collected bin bags there – lucky for him; otherwise he’d have been locked up for 23 hours a day – and helped other prisoners out with their letters and legal claims.

He says: “The stereotypical prisoner doesn’t exist, you know? The bad guy prisoner. I’ve never met that stereotypical thug with tattoos on his knuckles.”

Brixton is easier than the Scrubs for John, and he’s found NPR a real solace. “I took over The Rock Show and I said, ‘Look, I’m the new guy, you’ve got to take me by the hand, you tell me what you think is rock’. And then I came in on Monday, Tuesday, Wednesday, and there were like 20, 30 letters, kind ones, funny ones, and I was like, ‘Wow, they’re really listening, and they’re helping’. Because most people inside don’t listen to rock, we’re like a band of brothers.”

Prison radio isn’t just for those who become presenters, by any means: its true priority is its listeners. Research shows that 99% of prisoners are aware of NPR, 76% have listened to a show, and 37% listen every day. The average weekly listen is more than 10 hours. (I mention these stats to Scott Mills: he says he’d love to have such great figures.) An inmate has gone on record to say that NPR “saved my mind and soul at the start of my sentence”. Not only does it help new prisoners understand how prison works – its late-night show, Dream Time, promises “chill-out tunes and information on how to stay safe while you’re inside” – but, through its programmes, it tries to help them face up to the effect their actions have had on their families, on their victims, on society as a whole. And on themselves.

The organisation is remarkably pro-active: in 2015, NPR partnered with the Literacy Trust on a book club programme, and sent 400 books to listeners in 79 prisons. It has a yoga and mindfulness show, which is listened to by 75% of prisoners and helps them control panic attacks and anxiety. Each year, it receives more than 6,500 letters from prisoners, more than 3,000 requests or messages of support from families outside. Around 1,000 prisoners contribute to the yearly output, with more than 80 working as producers alongside PRA staff. And the PRA has just set up StraightLine, an online resource for prisoners when they get out.

Radio 1’s Scott Mills being interviewed at Styal. Photograph: Suki Dhanda/The Observer

In its early days, NPR struggled to fill its 24-hour remit. It played This American Life episodes for several years. At one point, there was a documentary strand, but this proved unworkable: docs are very labour-intensive and costly, plus there wasn’t really the demand from listeners. What the inmates prefer is informal discussion and interviews, with ex-cons, with governors, with big-wigs. They want to laugh or cry, they want honesty and real-ness. And they want music. Hip-hop and grime are popular (grime star Giggs spent time in Brixton), but there’s room for every taste, from electronic dance music to soppy tunes on The Love Bug. The request programmes get thousands of letters – impressive given that if prisoners want to ask for a track, they have to write a formal letter, with a stamp that they must pay for.

John likes working in NPR, because as well as playing requests and speaking directly to inmates, he can highlight some of their problems. “They want to hear about the issues,” he says. “Why didn’t they get their bail application through, or why are fewer and fewer people getting their tags… I mean, I’ve got a quite different accent than a lot of these guys from south London… but when we were all talking about stuff together, in language and terms they understand, it’s much more credible.”

He highlights a few big problems in prison. First: spice, the now generic term for what used to be called legal highs (not legal now). Spice is far harder to detect than marijuana in the user, which is why prisoners take it, but it has a much stronger effect. “In the Scrubs, I saw a man chuck himself off the bridge,” John says. “I was on the ground floor and I looked up, and there he was, on the fourth floor, stark naked, waving himself around and going, ‘Look, I can fly!’. His eyes were jet black, they were so dilated. They tried to grab him but he just threw himself back and over. Fortunately, there are nets…”

And there’s the understaffing. For Brixton Calling, an NPR show, John spoke to a prison governor. She told him she had the budget to employ hundreds more prison officers, but nobody is applying.

“And because there aren’t enough officers, everyone’s locked up for 23 hours. And when they get out of their cells, they have one hour, 45 minutes tops, to get a shower, phone their families, phone their solicitors, do whatever they need to do. And there’s four phones between 150 prisoners, so of course you are frustrated. And if you’ve grown up in a rough environment and you’ve got a tendency towards violence anyway, and you can’t call your mum and you promised you were going to call her today, you know…” He shrugs.

After John, I speak for a long time to Hilary, NPR’s poster boy. It’s hard to believe Hilary ever got to prison, he is such a model of an upright, God-fearing Brixton man. He’s from the Angell estate just along the road and he felt he let down everyone he knew when he was convicted. A successful man, designing training programmes for young people, he’d agreed to put his name to a cousin’s car-selling business without checking it out. When the business was done for what Hilary calls “a crime to do with tax”, he went down too. He tells me of the “dark cloud” that came over him when he was sent to Wandsworth. Luckily, he was soon assessed as low-risk and came to Brixton, though that brought its own stresses. He could see his old house from the wing. He only did radio production as a way to “get out of the cell, listen to music and play with IT and computers”, but he found he was good at it and then put himself forward to be a presenter.

Phil Maguire, chief executive of the Prison Radio Association, at HMP Brixton. Photograph: Suki Dhanda/The Observer

He says: “When I was working in the past, helping people with criminal offences get back into work, one of the things they always used to say to me was, ‘Well, you’ve never lived it. You don’t know.’ But I do now. The rollercoaster of emotions, of thoughts, of fears, remembering happy times, and just… you know, it really is down to your frame of mind, your mindset, what happens inside, and then beyond those gates.”

Styal doesn’t feel like a prison at all. With its three-storey houses, its cut grass and neat pathways, it has the feeling of a small university campus. Tucked away in the Cheshire countryside, it’s one of 12 women’s prisons in England. As such, it’s actually a higher category than Brixton. But the feeling is far less oppressive, especially on a bright day such as today. There are ducks so tame that they wander into the houses.

Inside the NPR studio, Scott Mills is being interviewed by a prisoner on his top tips for presenting. He mentions the usual “imagine you’re talking to one person” principle, but also, as a true Radio 1 DJ, says “don’t ramble on, play some music”. The presenter, who is still new to radio, is alert; she doesn’t just run down her list of questions, she listens, contributes.

We’re taken on a short prison tour, and I talk to Jane. She tells me that she phones her mum every day so she can speak to her eight-year-old daughter. Her daughter used to go to private school, Jane says, but doesn’t now. She was bullied over Jane being sent to prison.

“When I was out, everything was beautiful,” says Jane. “The house was beautiful and my daughter had everything, but I didn’t spend much time with her. When I get out, that’s going to change.”

Jane was raped, but didn’t tell anyone about it. She went into a depressive spiral and then, a few months later, when out drinking, she lost her temper and glassed someone. “I’m calmer in my head now,” she says. Her sentence means she will be imprisoned until 2019. She shares a narrow room in one of the houses, with two other women. All are mothers; pictures of their children – five in all – are stuck to their pin-boards. There is a one-up-one-down bunk bed that fills the back wall. Jane’s single bed is halfway along the side. Each of them has a small cupboard. The feel is of overcrowded student accommodation: cramped but neat, modern and clean.

Downstairs in this particular house, there is a nursery. It’s been graded Outstanding by Ofsted; the certificate is up on the wall. Styal has a mother-and-baby unit with nine beds. At the moment, there are eight mums, with nine kids between them, and one more baby on the way. The nursery worker I speak to isn’t worried by these numbers: “It usually works out,” she says, meaning the babies grow up into toddlers and leave, or the mothers’ sentence is served.

We’re shown the breakfast room – small, clean, bare. For breakfast, you get a carton of milk, a portion of cereal or a cereal bar, two pieces of bread and a cup of tea, with milk and sweeteners. In this house there are 22 women. But in the breakfast room there are only 16 places to sit, and you’re not allowed to eat in your cell. Such are the pettinesses of prison.

I don’t visit the wing, a building which looks like a municipal swimming pool from the outside. Things are tougher there, the women tell me. There’s lockdown in the evenings. Here, in the house, things are more relaxed – though not too much. “You can’t put your PJs on before seven in the evening,” I am told.

Inmates at HMP Styal in Cheshire on a radio course. Photograph: Suki Dhanda/The Observer

We return to the studio, talking all the way. HMP Styal provides a regular weekly NPR programme called Sound Women (nothing to do with the radio lobbying group). It’s an informative and – to an outsider – very touching show: inmates talk honestly about their experiences, both in prison and what they call “on the out”. What it’s like to be pregnant when you’re HIV positive and addicted to drugs; or, just as important, about what exactly happens when you get a prison visit. Women describe being a mother when your child is outside, how to manage. “Stay strong, think of your kid. If you think you’re gonna do something stupid in jail, just think of your kid. There’s light at the end of the tunnel. One day you’ll be out, won’t ya?”

It’s a cliche, but one that contains truth: many of the women behind bars are there because of their association with men. There are a few drug mules, several drug-users, lots of women who have been coerced into selling sex. Violence is part of their lives; lashing out physically while drunk is very common. This turns inward when they go to prison. Self-harm is common, and inmates attempt suicide. A prisoner tells me that some women hurt themselves in order to be found, timing their self-harm for nine o’clock at night when the prison officers come round.

Radio is about giving people a voice, and there’s a sense in which NPR helps the women in Styal learn to speak up. To say what they think; to speak when they used to be silent. “Perhaps they might be able to say ‘No’ when a boyfriend asks them to hide a weapon,” says an NPR producer. “Or, at least, to ask for help.”

The difficulty of asking for help is brought home to me when I talk to Ellie. She has some mental health problems, but a lot of charm. She left Styal a few months ago on probation, but has ended up back inside. When she was free, her medication didn’t turn up; she couldn’t cope with her assigned accommodation (she had a camp bed, the shower didn’t work); she didn’t have the wherewithal to sort it out. “No one smiles at you, out there,” she says. She ended up back on heroin and got sent back to Styal. She talked about her experience on NPR.

Ellie cries a bit, when I talk to her. I don’t. But it is her I think of a few weeks later, when I go into Brixton prison again, for a special evening. For its 10th birthday, PRA joins up with Letters Live. In the prison chapel, in front of an invited audience, celebrated actors and three ex-prisoners read out letters relevant to imprisonment. Kate Tempest is one of the readers, and she breaks down in the middle of reciting part of her poem Brand New Ancients. It’s the bit that goes, “We are still permanently trapped between the heroic and the pitiful”, and I think of Ellie, and of all the other prisoners, locked up, lying down, listening in.

The names of all prisoners except Kedia and Hilary have been changed

Click here to donate to the Prison Radio Association

National Prison Radio: a brief history

1994 Mark Robinson and Roma Hooper approach governor of Feltham young offenders institution with an idea to set up the UK’s first prison radio station; it is launched the following year.

2005 Phil Maguire (producer/reporter on BBC Radio 2’s Jeremy Vine Show) becomes BBC Prison Radio project manager, running a partnership between the BBC and the Prison Service.

2006 The Prison Radio Association (PRA) charity is formed. Roma Hooper is founder and chair. Phil Maguire leaves the BBC to become chief executive.

2007 The PRA launches Electric Radio Brixton in HMP Brixton, the UK’s first prison radio station. It broadcasts 24 hours a day, seven days a week. The launch show is co-presented by the BBC’s Bobby Friction and a serving prisoner. Mick Jones from the Clash and Billy Bragg are the first studio guests; together, they perform Should I Stay Or Should I Go.

2009 Electric Radio wins four Sony awards; later in the year it relaunches as National Prison Radio.

2010 The PRA sets up a prison radio project at HMP Styal in Cheshire.

2012 The PRA-produced programme Face to Face, where three victims of violent crime meet three people serving time for similar crimes, wins a Sony Gold award.

2013 NPR is available in 100 prisons in England and Wales.

2015 NPR broadcasts Bound, a drama produced with BBC Drama North based on interviews with inmates at HMP Styal.

2016 PRA wins charity of the year at the Third Sector awards; PRA-Radio 4 documentary The Abuse Trial wins a Rose d’Or; the Letters Live show from HMP Brixton is broadcast live on NPR; Hooper is appointed an OBE. MS