Measuring change in the school system over a particular period is not an easy exercise. In the past 100 years, inflation has played havoc with the value of money, and class sizes do not reflect the growing breadth of a teacher's job. One measure that can be used, and has been calculated in the same way for the past 100 years, is the pupil-teacher ratio (PTRs).
Using government data, and bearing in mind that although Scotland and Northern Ireland have managed their own education system for the whole of the last century, Wales only really became a separate entity a decade or so ago, it is possible to construct a timeline for PTRs.
A hundred years ago, in 1910, it was not really possible to talk of primary and secondary education. There were elementary schools, covering the five-14 age-group, and selective schools for those who passed the examination to grammar school. In the elementary sector, PTRs across England and Wales averaged 37.2 pupils per teacher, whereas in the secondary schools they were 16.0 pupils per teacher. No doubt class sizes were generally much larger. Indeed, in Scotland, PTRs were worse than in England and Wales and remained so until the Second World War, as they were in Northern Ireland until the 1970s in the secondary sector, and the 1990s in primary schools.
Despite the ravages of the First World War and the economic turbulence of the 1920s, PTRs in the elementary sector were on an improving path. The new generation of grammar school pupils attending Mr Balfour's county schools, and their fellows in the emerging urban secondary modern schools, were less fortunate, as secondary school PTRs deteriorated between 1910 and 1940. This was mostly due to the nascent post-11 sector that was starting to emerge in enlightened urban areas.
The decision in Butler's 1944 Education Act to create separate primary and secondary sectors, following the Hadow Reports of the 1930s, meant that by 1950 secondary PTRs had peaked in England and Wales, and primary ratios had remained virtually unchanged for the previous decade.
By 1960, investment in education meant a period of largely unbroken improvement in primary PTRs had begun. The hiccup in 2000 is one of the blemishes on the early record of the Blair government.
The 20 years between 1970 and 1990 that encompassed the advent of Mrs Thatcher as education secretary and her downfall as prime minster were the golden years for secondary education - at least, as far as PTRs were concerned. The 1990s saw a reversal, as deteriorating economic conditions coincided with the start of a rise in school rolls and a rise in the number of pupils voluntarily staying on beyond the age of 16.
Spending during the first decade of this century has restored most of the gains lost in the 1990s. But PTRs in both Scotland and Northern Ireland are still better than in England and Wales.
Currently, there are rising pupil numbers in the primary sector and falling rolls in the secondary sector. PTRs are likely to be watched carefully to see whether money follows the pupils under the coalition Government. If it does, even the pupil premium may not be enough to save the jobs of several thousand secondary school teachers over the next few years.
John Howson is director of Education Data Surveys, part of TSL Education.