Kay’s highly influential work contributed to the creation of children’s panels and the special unit at Barlinnie for violent offenders, but perhaps her most famous work was her spell living on a breadline income in Glasgow’s East End close to where she was born and brought up.

Those three months in Lilybank formed the basis of a landmark BBC documentary in 1977.

Kay was born in Shettleston to a Catholic mother and Protestant father. When she was four years old, she was sent to a convent school in Girvan but after she contracted polio and was taken to hospital, she fell below the radar of the education system for some time and was forced to educate herself.

Every day she would feed her passion for knowledge, particularly history, by visiting Tollcross Library. She would read one book in the morning and sometimes go back for another after lunch. The bench where she sat was, until recently, still there.

After training at Edinburgh University, Kay began her career as a psychiatric social worker in the late 1950s, working with borstal girls in prison. In the 1960s, she became a lecturer at Glasgow university, setting up its probation training course, the first in the country. It was the first – and not the last time – she would change the landscape of her chosen field.

Kay later moved into social policy work and was a member of the Kilbrandon Committee which led to the Social Work Scotland Act 1968 and the establishment of the children’s panel structure. It is not only still in place more than 40 years later but has been admired and emulated around the world.

For nearly 50 years, Kay was a member of the Labour Party. At times it was a close relationship, at times more distant and eventually it ended in divorce. She joined in 1945 and later became a part-time member of Harold Wilson’s policy unit at Number 10. The relationship with the party reached breaking point however in 1994 when Tony Blair was elected leader.

“She left when Blair was made leader,” says her husband, Professor David Donnison, “because she spotted that he was not going to be leader of a party that she could belong to.”

After leaving Labour, she joined the Scottish Socialist Party until they imploded before finally becoming a member of the SNP. Despite her anti-authoritarian instincts, she always felt she needed the berth of a party. She realised, says her husband, that we all have to take responsibility for what is happening in society but also realised that you can’t do it by yourself – you have to have troops, a movement, to bring about change.

Between 1975 and 1980, Kay was deputy chair of the Supplementary Benefits Commission. It was through her work with the commission that she met David Donnison. Her first husband was the MP Neil Carmichael, with whom she had a daughter Sheena.

It was while serving on the commission that Kay decided she ought to experience the living conditions of the people her work was designed to help.

She took leave from Glasgow University and got a flat in the Lilybank area of the city. For three months, she lived, incognito, on a similar income to a person living on benefits.

In her vivid testimony, she talked of her fear of the aggression in small children and the temptation to steal as she tried to live on £10 a week. The three months not only led to the controversial BBC documentary, they highlighted and underlined the central philosophy of Kay’s life and work: that public services must be more humane and that benefits more generous.

In the early 1970s, Kay worked part-time in Barlinnie where she helped to set up a special unit for men serving life for violent crimes, the idea being that prisoners and staff would work together. Later she was to have more direct experience of prison when she was sentenced to 14 days for breaking into the Faslane nuclear base.

Kay was always passionately anti-nuclear and for seven years lived in Ardentinny near the base from where, with other members of the women’s peace group the Gareloch Horticulturists (or Horts for short) she would launch benign raids on the enemy.

On one such trip to plant bulbs just beyond Faslane’s perimeter fence, she was caught and charged but refused to pay the fine. After a few days in Cornton Vale, much to her annoyance, someone else paid up and she was released, late at night with no transport. Luckily a passing motorist picked her up and took her home; it turned out to be one of her former students.

For many years, Kay wrote for The Herald and also published two books. Sin and Forgiveness, which emerged from a PHD in theology and English awarded to her when she was 76, looked at how we formulate moral principles without the old guiding routines provided by bodies such as the church, while in 1991 she wrote Ceremony of Innocence: Tears, Power and Protest which argued that men should feel more able to cry and women to feel angry.

The idea of being able to express our emotions freely is well accepted now of course, but in those days - as ever – Kay Carmichael was ahead of the game.