IT began with a nun and a conversation about a black pudding in a Glasgow tenement.Doreen Grant, from the Catholic religious order of the Sisters of Notre Dame, had arrived in a run-down estate in an area of Govan know as Wine Alley with a mission to find out why pupils from poorer areas struggled at school.

As a former teacher with 20 years experience in Glasgow and Liverpool, she was convinced children from deprived backgrounds labelled as lacking in intelligence or effort were lacking neither, but wanted to prove it.

Controversially, she also believed a "strange kind of agreement" existed between inner-city parents and teachers that allowed continued failure to be excused under the smokescreen of these two negative stereotypes.

In addition, she felt communication between parents and their children in deprived areas was a contributing factor to difficulties at school, noting that "being a good boy" in many homes seemed to translate as "stay out of this conversation and do not distract the adults".

And so it was Sister Grant turned up in Wine Alley in 1974 and started knocking on doors and asking parents to speak to her.

She did not find the going easy. Her first attempts at explaining her educational theories did not sit well with the few families prepared to give her the time of day, partly because she had problems with communication of her own in a world that was alien to her. Enter the black pudding.

"Could you describe a black pudding?" she asked one group of four mothers. "It's black." "It's long." "And it's round," came the responses.

"Could I eat it?" she replied and the penny dropped. The mothers realised for the first time what she was getting at - that the use of words could be vague and misleading or precise and enlightening and that, crucially, it was in their gift to make them the latter. And if their offspring could be armed with those same skills then perhaps the Govan skyline was no longer the limit.

The project went from strength to strength and, over the next decade, more groups began, schools became involved and officials from the former Strathclyde Regional Council began to take note.

Much has changed since the 1970s in the understanding of how education in the early years can transform people's lives but, now in her 80s, Sister Grant believes exactly the same issues that she began to grapple with in a Glasgow tenement 40 years ago exist today.

In her 1989 book about her experiences, Learning Relations, which earned her a Phd from Glasgow University and which has just been reprinted by Routledge, she quoted research from the 1970s which found the best predictor of children's achievement was their home address.

In 2007 a report by the Organisation for Economic Co-operation and Development into Scottish education came to much the same conclusion.

It is astonishing and depressing in equal measure that a greater impact on educational equality has not been achieved in the intervening years, particularly when, as Sister Grant has demonstrated, some of the most profound solutions are the simplest.