As the century advanced the old rough and visible class categories became more blurred, more challenged as to their legitimacy and more blessed with opportunities to rise out of a particular class through secondary and even higher education. By the end of the century, millions of the children of manual workers had risen into non-manual jobs and many thousands had become the graduate grandchildren of butchers, bakers and candlestick-makers, following professional careers.

The class structure had shifted. In 1900 the vast majority of Britons were elementarily schooled proletarians: by 1970 Stevenson’s classification divided the employed half and half between white- and blue-collar jobs: by 2000 the balance will have been tipped decisively to form a button-pushing majority dominating a minority of the remnants of the former working class.

The Office of National Statistics (ONS) noticed that the traditional class causes of inequality in voting, health, income and education were now challenged by new sociologies of gender, ethnicity and region. It therefore asked the Economic and Social Research Board to revise the old (Stevenson) five-fold classification.

The ESRC set up a committee which has now reported and, inter alia, placed all teachers from primary schools to university graduate divisions in Social Class 1. The context is wider. A new “socio-economic classification” (SEC), it is hoped, will carry us through the 21st century and improve our understanding of society in “its more opaque and subtle stratification processes”.

How has this apparent promotion of the teachers come about? Basically it is because the committee of sociologists has recognised the important fact that teachers, in the course of the century, have become professionals. More generally, precisely because social classes have become less sharply differentiated and less obvious to the eye of common sense, sociologists have exerted themselves towards clearer definitions and measurements.

They have analysed the concept of class, distinguished it from status and from power and clarified employment relations and conditions. Under the old scheme ownership, skill and scale of organisation were paramount in drawing up stratification categories. Now the further concept of the labour contract contrasted with the service bargain takes precedence over more traditional elements such as skill. The labour contract is a short-term market exchange of supervised effort in return for weekly or hourly pay. The service relationship is a long-term exchange of service to the aims of the employer in return for a secure salary, extended tenure and the associated features of a career, including present autonomy, future possibilities of promotion and a comfortable working environment.

The professions constitute the purest form of the service relationship, unadulterated, as so many intermediate occupations are, by the elements of a labour contract.

The 20th-century history of teaching is a story of advance towards an organised and unified profession: recruitment has gradually eliminated the uncertificated and raised the qualifications of entrants, salaries are monthly, the pay scale is recognised, notice of leaving is a month or more,there are opportunities for promotion, hours are negotiated, the design of work (though constrained by the national curriculum) is largely left to the individual teacher.

All this sounds splendid. But wait. The committee also strongly recommends that the classes represent a group not a ranking. Thus any notion that, by government fiat at least, teachers have been collectively promoted to the top class and at the same time unified is, unhappily, a fairy tale.

Government fiat is unlikely in any case to affect the real world of relationships with students, parents or other teachers. Some, like me, would unhesitatingly put them in the top class, along with dedicated mothers and others whose main concern is with nurturing the next generation. But remember the “Holmes-Morant” secret circular of 1910: ”. . . apart from the fact that elementary teachers are as a rule uncultured and imperfectly educated . . .”

There is still a long way to go before this status sneer is obliterated. A Teaching Council for England and adequate salaries for the UK have yet to be realised. The new classification still treats state and private schoolteachers as one category.

But no parent rich enough to pay accords equality of status to the master from Harrow and the teacher from the local comprehensive. Apartheid is the term used by George Walden to describe the gap. While such heterogeneity remains within the category I would need strong persuasion from my fellow sociologists that teachers in private schools do not belong to a separate and superior class.

A H Halsey is emeritus professor of social and administrative studies at Oxford University