In the mid-1960s when the Plowden committee was sitting, consensus reigned among the liberal-minded elite who thought about education. The country was beginning to emerge from a political and cultural Dark Age. The economy had boomed under Harold Macmillan; the Beatles had arrived; new universities were springing up; and primary school classes were loosening their stays. Optimism was in the air.

That is not to say that Plowden was free of conflict; there were big debates about religious education (several members said that children under 12 were too young to understand theology), nurseries and the age of transfer to secondary school. But, as Professor Maurice Kogan, the secretary to the committee, says: “There was remarkable consensus about what was accepted as good primary practice.” Or as Professor David Donnison, a committee member, said: “What we did have was a conviction that education could play an important part in making the world a better place.”

Why was the report commissioned? Simply because it was the turn of primary education to be investigated by the Central Advisory Council for Education, a standing committee set up to advise the then Minister of Education, Sir Edward Boyle. Plowden started in 1963 to “consider primary education in all of its aspects, and the transition to secondary education”.

So, it was not a response to any crisis. Surveys of the time showed children’s reading and comprehension to be improving. The number of young people taking and passing O-levels continued to rise as did the number staying on at school.

The committee of 25 included 14 directly involved in education and a number of expert outsiders. In the latter category was: Lady Plowden herself, a juvenile court magistrate; AJ Ayer, the Wykeham Professor of Logic at Oxford; Timothy Raison, editor of New Society; David Donnison, professor of social administration at the London School of Economics; Ian Byatt, then a lecturer in economics at the LSE and now the man in charge of OFWAT (Office of Water Services); and Michael, now Lord, Young, originator of the Open University and the Consumer Association, who was then chairman of the Advisory Centre for Education.

Such people representing the new disciplines of sociology and social administration provided the intellectual ballast. They were joined by Professor JM Tanner, professor in child health and growth at London University, who was responsible for the chapter on child development. There were also two “housewives and parents” on the committee: Moira Bannister, now Lady Bannister, and the Hon Janet Campbell, who was prominent in the Campaign for the Advancement of State Education.

It was an impressive collection of the great and the good. David Donnison, now emeritus professor of town planning at Glasgow University, knew Lady Plowden beforehand. “I knew it was going to be a constructive, purposeful and hard-working group because that’s the sort of lady she is,” he says.

Lady Plowden dominated the show. She made the main decisions on the shape of the report and on its style. On strategic issues, such as the age at which children should enter or leave primary education, she put together the arguments.

Towards the end of the committee’s life, she worked more than a full week on the report. Lord Young also remembers the hard work: “I must have visited 100 schools in three years.” The committee met as a full body at least once a month for three years. Much of the work went on in sub-committees. Many of the later meetings where draft chapters were being considered took place over weekends. Plowden visited 23 English local authorities, 289 schools, colleges and universities in England and Scotland, and also travelled to Russia, Poland, Denmark, Sweden, France and the United States. The committee also asked the Department of Education and Science to fund a longitudinal study, which has since become famous as the National Child Development Study.

The research supported some of the main conclusions about the impact of social background and parental attitudes on children’s progress, which fed into the proposal that parents be involved in their children’s education. Similarly, the research on economic and social factors provided justification for priority areas - giving more money to schools in deprived districts.

Lord Young wrote the first draft of the chapters on parents and on educational priority areas (EPAs). He was pleased when visiting a Tower Hamlets school recently to find that they were still getting a bit of extra money on an EPA index. His recollection is that there was no disagreement on the committee about Britain espousing positive discrimination for the first time. Ian Byatt, though, is not so happy about such positive discrimination now.

The big discussions on issues such as nursery education resulted in notes of reservation at the end of the report. Moira Bannister was worried that a nationwide extension of nursery education would result in more working mothers. Eight members - including Lady Plowden, AJ Ayer, and Michael Young - favoured having parents contribute to nursery education costs because resources were so tight.

In Advisory Councils and Committees of Education, Professor Kogan writes: “The Plowden report was climacteric as a statement of belief in social engineering. ” It reinforced progressive education in many schools and it was feted abroad, particularly in the United States.