JOHNNY STEELE did not trust the offer to go to HMP Barlinnie’s Special Unit (BSU). He feared psychiatrist and art therapist Joyce Laing might send him to HMP Carstairs … and from there he might never get out.

Jimmy Boyle, one of Scotland’s most notorious prisoners didn’t trust her either, Ms Laing remembers: “He was suspicious. He thought this was too good, it couldn’t be happening. He thought ‘this woman must be a spy’.”

Boyle himself had been transported to the unit – created to take some of Scotland’s most violent and uncontrollable prisoners – in a van, escorted by outriders and a police helicopter.

“I saw it on TV,” Ms Laing remembers. “I thought ‘all this for one man?’”

Now the work of the Glasgow jail’s extraordinary experiment in humane imprisonment is being explored in a new exhibition at Glasgow’s Kelvingrove Museum, based on Ms Laing’s own collection of sketchbooks, newspaper cuttings and photographs of the time. It includes painting and sculptures by prominent inmates and photographs never before displayed in public.

The unit was open for 21 years, from 1973, during which time Boyle emerged as a sculptor whose work fetched premium prices – not least because of his notoriety – but other prisoners with talent such as Hugh Collins and Bob Brodie were also “discovered” through work with Ms Laing, Scotland’s first art therapist.

The exhibition, the creation of Glasgow Museums’ Open Museum outreach service was curated by modern-day inmates at Barlinnie. It aims to shed light on the way the BSU gave a chance to men who had until then served most of their sentences in solitary confinement.

Claire Coia, curator of the Open Museum said it would encourage debate about the benefits of creativity in prison. Given the controversy over some of the crimes committed by those who stayed in the unit, she and other curators are on hand to discuss the issues it raises with visitors.

Prisoners involved in the exhibition have gained skills such as conservation, she said. “We’ve had positive response from everyone involved.”

It is an insight into an idea that influences prisons to this day, Steele claims. “No other prison in Scotland would take me and it saved my life. A lot of the guys who went in there and came out didn’t go back into prison,” he said. “The unit played a key role in changing the way we tried to reintegrate people, it’s still seen today.”

Barlinnie Special Unit – A Way Out of a Dark Time is at Kelvingrove Museum until June 3 2017. Talks, tours and a film screening will be taking place throughout May.