Fine Cell Work has been teaching needlework in high-security prisons for 15 years. Now the charity has won the highest honour for a volunteer group, and opened a pop-up shop selling the prisoners' work. Huma Qureshi meets the volunteers

Frankland prison in County Durham is notorious. The high-security, men-only jail has housed some of the most dangerous criminals in the country, including Charles Bronson, Harold Shipman and Ian Huntley. Three months ago, two inmates there murdered and then disembowelled another.

It's not the sort of place where you might imagine a spot of cross stitch would go down well. But for more than six years Linda MacMullen, a grandmother and part-time French teacher, has been going to Frankland every fortnight to teach needlework to a group of 12 prisoners. She wears a personal alarm around her neck every time she goes in, and two prison officers stand outside the open door as she teaches.

"I know all the men who come to our class are in there for life sentences. I assume they are responsible for killing someone, but I don't know that. And I don't want to know. I just don't," she says. "But I also think they are different people now to who they were. You can't be in a prison for 10, 15 years and still be that same person."

MacMullen is one of 200 volunteers with Fine Cell Work (FCW), a social enterprise and charity which trains prisoners in paid intricate needlework, producing cushions, wall hangings and quilts. Most volunteers help out at the charity's offices – but 60 of them, like MacMullen, go into jails to work directly with prisoners.

On Monday, the charity was presented with the Queen's award for voluntary service, the highest possible honour that can be given to a volunteer group. FCW's founder, Lady Anne Tree, who died in 2010, spent decades lobbying the government to change the law to enable prisoners to earn money from their cells, before officially launching the charity in 1997. There are now more than 400 prisoners in 29 prisons across the UK making FCW products.

It has been a busy time for FCW: the charity's first retail space opened last month (albeit a temporary one), a pop-up store in Mayfair. Products for sale include hand-embroidered cushions in retro geometric patterns, tote bags emblazoned with the word "swag" and pretty patchwork quilts. Big names in the craft world including Emily Peacock, Cath Kidston and Daisy de Villeneuve came up with designs specifically for the shop, which the prisoners then stitched up. The pieces aren't cheap (there are cushions for £150), but reflect the painstakingly long hours that go into each item – one cushion can take 100 hours to make, while a quilt takes a year.

Next week the shop will be hosting craft events as part of the London Design Festival, including an all-day stitching session where members of the public can drop in and sew a message to a prisoner.

Almost all of the volunteers who teach needlework are women and the majority of the prisoners are men. It can make for a challenging dynamic, says Piero Donat, who works in FCW's head office. "It is tough. We need to know the volunteers can work in a prison environment. Some prisoners haven't been taught by a woman before."

Caroline Wilkinson is a retired teacher from south-east London. She started volunteering to teach patchwork and quilting at Wandsworth prison 12 years ago. Recently, the wing where she taught closed and the classes have since moved to Brixton jail.

"Wandsworth prison is pretty horrific. The physical surroundings are really intimidating. But inside the people are like you and me," she says. "That's what I've come to appreciate."

In the early days of her involvement with FCW, Wilkinson said she didn't want to go in a men's jail. But Katy Emck, the charity's CEO, persuaded her to give it a try. "She said: 'It might not be as bad as you think.' And she was right."

Wilkinson teaches three groups of 12 once a week. "I did wonder how quilting would go down. It's not a very macho thing and I didn't think it would be attractive to them. But then 27 men turned up to my introduction, and I realised they just wanted to do something. The chance to earn money was a motivation, but not the only one. They are bored out of their minds and a lot of the prisoners just want to do something meaningful. And they can – just because they are in jail, it doesn't mean that they don't have practical or creative skills."

Marjorie Coles is a former nurse who used to teach quilting to local women in her spare time; now she teaches a group of 10 male prisoners at Bullingdon prison in Bicester.

"Very occasionally there will be someone who I can tell is thinking, 'Oh, you're just a woman', but I ignore it," she says. "My group is not aggressive or high-tension in any way, and works well together. They tell me they are much less wound up now when they are in their cells because they have something to do. I wouldn't say I know them very well, but I don't see them as prisoners. I see them as people."

FCW prepares its volunteers for going into prison as much as it can. It advises them not to ask about crimes committed – "The important thing is not the crime, but that the prisoner is trying to take a step towards changing his life," says Donat – and cautions against sharing personal details.

But the volunteers say it's natural to form some sense of attachment and pride, especially when work is finished and handed in.

"The change you see in the men who come to the classes is amazing," says MacMullen. "At first, they tend to be withdrawn. They won't make eye contact and won't talk, or lean away if you sit next to them. But slowly, with encouragement, they start to see what they are capable of. They start to talk, help each other. One man told me he was always being put in solitary [confinement] for fights, but that since he'd taken up stitching he didn't get put in there anymore. Instead of fighting, he's in his cell, stitching for hours and hours. That's the difference this makes."

Hanging just inside the entrance to the pop-up store is a cream quilt with embroidered maroon birds in flight. It was made by one of Wilkinson's class members, and she called his sister to let her know it was there. "She is absolutely devastated that he is in prison. It's the first time anything like that has happened to their family. But his sister is just so proud of the work he's doing, and knowing that has given him self-esteem too," Wilkinson says. "It's just so extraordinary that craftwork can make such a difference."

• A volunteer will speaking about her experience of teaching embroidery to life-serving prisoners at the FCW pop-up shop at 5 Grosvenor Street, London W1K 4DJ, on 26 September.