The idea that teachers can be active trade union members has long struck many parents as an oddity. Seeing miners and industrial workers on a picket line made sense. But teachers? Middle-class professionals don't go on strike, do they?
Some teachers have themselves felt uncomfortable taking an active part in trade unions. A TES front-page story in 1923 reported on calls from teachers' union members to join the Trades Union Congress (TUC). "They have, however, been equally warmly opposed by other members, who were instinctively averse from identifying their position with that of manual labour." That snobbery may be one explanation why it took the National Union of Teachers until 1972 - more than 100 years after it was founded - to officially affiliate to the TUC.
Yet while the unions representing "manual labour" suffered sharp declines in the past century, those for teachers did not just survive, they flourished in membership terms.
Between 1910 and 2010 the total population of England and Wales grew by a half. In that same period, active membership of the NUT doubled to roughly 200,000. More surprisingly, a breakaway faction from that union grew from small groups of male teachers meeting in cafes and restaurants to become a separate major union, the NASUWT. It now has more than 200,000 active members, so is arguably bigger than the NUT.
The rise in teacher union membership clearly reflects the increase in teaching posts available. New teachers today join unions automatically, often just as a form of insurance in case they are subject to an accusation, or face redundancy. But such protection has always been a reason to join: back in 1878, for example, the NUT fought the legal case of a teacher accused of obtaining science and art exam papers and passing on details to his pupils.
Teachers' unions argue that they have also helped to improve their members' pay and working conditions. This is also undoubtedly true. Their early campaigning helped bring an end to "payment by results", a system in the 1880s and '90s where schools were funded according to their pupils' performance against limited measures of the 3Rs.
By 1900, six key teaching unions existed: the NUT, the National Association of Head Teachers, and the "joint four", associations representing secondary headmasters and mistresses and assistant masters and mistresses (ancestors of today's ATL and ASCL).
A crucial victory for the NUT in the early 20th century was the introduction of national salary scales for teachers. These were negotiated by the "Burnham committees" that ran from 1919 until 1988 and included teachers' unions representatives. But winning the scales was not enough - teachers had to fight to ensure local authorities stuck to them.
In 1922, a time of severe public sector cuts, teachers accepted a 5 per cent salary cut, but only if it was based on the national scales. Some local authorities tried to introduce even bigger cuts the next year, and teachers hit back, closing schools for 14 weeks in Southampton, and 10 weeks in Gateshead.
The Daily Mail was outraged, writing that: "Public opinion is deeply aroused by the rapacity of elementary teachers, by their truculent and inflammatory methods of agitation, by their frequently unfortunate influence upon the young children committed to their care."
The most dramatic strike in the period began in April 1923 in Lowestoft, Suffolk, where at least 167 teachers refused to work in the authority's schools for 11 months.
The council refused to back down on its plans to reduce their salaries by 10 per cent, and advertised for replacement teachers, bringing in 112 from outside the area.
But the NUT had support from many local parents and their children, perhaps more sympathetic to trade unions than families today. "Some parents, acting on a resolution passed at a mass meeting, refused to send their children to school on Tuesday, and in one or two instances some of those who attended became unruly and had to be curbed by the presence of policemen," The TES reported on 5 May. "About a thousand small boys and girls, with banners, rattles and flags, were led in procession through the town".
The TES provided regular updates on the "astonishing situation" in Lowestoft, where the striking teachers set up alternative schools, which it called "welfare centres". "The officials of the National Union of Teachers state that the centres will be opened at the request of dissatisfied parents, and that children will be looked after by the dismissed teachers instead of running about the streets," the newspaper said.
About 1,300 children were educated in the centres, while the remaining three-quarters of the elementary pupils in Lowestoft were taught by imported teachers. The local authority tried to prosecute a group of parents in June for withdrawing their children, but the case was dismissed by magistrates.
After 11 months (during which a general election was held, and new discoveries made in the tomb of Tutankhamun) the dispute was resolved in the teachers' favour. The strikers had been sustained at a cost to the NUT of about pound;44,000.
The huge work that went into establishing and maintaining national pay scales goes some way to explaining why unions are now alarmed at the speedy rise of academies, which do not have to follow them.
The NUT tends to be caricatured today as the most militant union. But at many points in the 20th century it was the NASUWT - or its predecessor, the National Association of Schoolmasters (NAS) - that could be more militant and awkward.
The NAS now risks looking like a historical oddity as it was set up by small groups of male teachers in opposition to equal pay for women. Nigel de Gruchy, former NASUWT general secretary, has acknowledged the union was clearly "on the wrong side of history" on that issue.
But at the time, many male teachers felt they were not paid enough to support their families; they were concerned that equal pay would mean lowering men's salaries, rather than raising women's. They also feared that the NUT was not fighting their corner; some even recalled receiving NUT papers promoting equal pay while they were under fire in the trenches during the First World War. The NAS broke away from the NUT in 1922, after voting that its members could no longer join both.
A topic that could anger both unions in the past, as now, was pensions. In 1953, Florence Horsbrugh, education minister and former teacher, said that teachers' pension contributions would be increased from 5 to 6 per cent. Unions attacked the plan as the equivalent to a 1 per cent pay cut, and union meeting attendance rocketed.
At the time, teachers in 27,520 schools were involved in collecting money for the National Savings Movement, putting in savings brought in by two million pupils. The NUT asked its members to stop collecting savings, but refused to go as far as the NAS, which took the more disruptive action of stopping the collection of dinner money.
Another year during which the NAS took action against the will of the NUT was 1961. Then it organised a range of national rallies and strikes, starting with the one-day closure of William Penn School in London. Its chief motive was to press for the NAS to have a place on the Burnham committee alongside the NUT so it could influence teachers' salaries.
The NUT was appalled, suggesting the actions were selfish. But several politicians agreed that the NAS deserved a place on the committee, as did The TES, which wrote: "On the grounds of equity alone the NAS deserves to be considered." The NAS campaign succeeded that year, a turning point for recognition of the younger union. (Ironically, it was the same year that equal pay for teachers was introduced, defeating the NAS's original aim.)
The two bigger classroom unions turned more militant together in 1969, when a disappointing national pay settlement led them to embark on a series of co-ordinated strikes across Britain. It was in response to these actions that a non-striking education union, the Professional Association of Teachers (PAT), was launched.
Further strikes were held in the 1970s, but industrial action peaked between 1984 and 1986 when the NUT and NASUWT held two years of national and local rolling strikes. This time, the NUT ended up appearing more militant than the NASUWT; both lost members to PAT and AMMA, the future ATL.
"The 1980s pay dispute was characterised by inter-union rivalry and division, and division within unions themselves," the NUT's own mini- history notes. "Some in the NUT felt the final pay settlement was too modest, yet it was a fact that the union lost nearly a third of its membership during these years."
The TES was usually more sympathetic than other media to the teaching unions, but it tended to argue against industrial action. In 1923 it had supported the unions against local authorities on pay, but said it was "a subject for general consideration and not for strikes or lock-outs".
When the NASUWT held refusals-to-teach in 1974, as a way of tackling the behavioural problems of specific pupils, The TES warned that the actions would create too much adverse publicity, and have a "goldfish bowl effect" on "stinking fish". Likewise, when the NASUWT voted to boycott Sats tests in 1993, The TES "heaved a weary sigh", noting that "there is no chance that the union can win (and) that all tests should be scrapped and rewritten". An appeal court ruled later that year that the dispute was legitimate.
The bitterness between the unions continued into the '90s. Some hopes were raised for unity in the Noughties, but they were scuppered by the rows over the workforce agreement, signed in 2003 by Government and all teachers' unions except for the NUT.
The agreement created a range of benefits designed to reduce teacher workload, including statutory time for planning, and signatories could take part in the "social partnership" discussing plans for education with the Government.
But the NUT was suspicious, warning that it would lead to unqualified teachers taking charge of classrooms, and took out full-page adverts in The TES attacking its rival unions and calling them "collaborators".
In its millennium edition, The TES wrote: "If the unions were seen 100 years ago as dangerous forces for progress, now they seem close to being tarred unfairly as forces of conservatism, to use the phrase Tony Blair minted."
The current Government is even more likely to regard unions as part of "the blob" - the education establishment holding back schools. Yet the unions' future is certainly secure for now. The way staff pay their subs has changed over the century, from the union rep going round collecting cash to direct debits. But when cuts and redundancies loom, as they do now, teachers make sure they pay them.
1870: The National Union of Elementary Teachers (NUET) is founded at a meeting at King's College, London, to represent teachers in England and Wales
1874: The Association of Headmistresses is founded
1884: 180 women teachers meet to set up the Association of Assistant Mistresses (AAM)
1889: The NUET becomes the National Union of Teachers
1890: The Headmasters Association is formed
1891: The Assistant Masters Association in Secondary Schools (AMA) is formed
1897: The National Federation of Head Teacher Associations is formed (later becoming the National Association of Head Teachers)
1909: The National Federation of Women Teachers joins the Women Teachers' Franchise Union to form the National Union of Women Teachers
1913: The NUT campaigns for a national salary scale
1919: The National Association of Men Teachers is formed within the NUT to promote the interests of male staff. The Burnham Committee on pay for teachers introduces national pay scales for elementary teachers
1920: The NAMT changes its name to the National Association of Schoolmasters (NAS)
1922: A vote at its annual conference bars NAS staff from remaining members of NUT
1945: The National Union of Uncertified Teachers, set up in 1913, joins the NUT
1950: Durham attempts to dismiss all employees who were not members of a trade union. Although nearly nine out of 10 teachers in Durham were NUT members, the union fights plans for a closed shop, winning in 1952
1953: Florence Horsbrugh, minister for education, sparks fury from unions by asking teachers to accept an increase in their contributions to the pension fund from 5 to 6 per cent
1961: Equal pay for male and female teachers is introduced, and the NUWT disbands having achieved its mission.
1965: The Union of Women Teachers (UWT) is formed after a campaign by a group of female teachers in Brighton over the disrepair of their school
1970: The Professional Association of Teachers (PAT) is formed, becoming Voice in 2008
1976: The NAS and UWT merge to form the NASUWT, partly as a consequence of the previous year's Sex Discrimination Act.
1977: The Association of Headmistresses and The Headmasters Association amalgamate to form the Secondary Heads Association (SHA)
1978: AMA and the AAM merge to form the Assistant Masters and Mistresses Association (AMMA)
1987: The Teacher Pay and Conditions Act marks the end of the Burnham committee, which negotiated teachers pay
1993: AMMA is afforded recognition in further education, and becomes the Association of Teachers and Lecturers (ATL). The NASUWT achieves victory when the Appeal Court rules its boycott of national curriculum tests a legitimate trade dispute
1995: Demonstrators at the NUT conference jostle shadow education secretary David Blunkett, who retreats into an office
2003: Teacher workload agreement signed by employers, Government, and unions (except NUT)
2006: The SHA changes its name to the Association of School and College Leaders, to reflect the fact about two-thirds of members are not heads
2008: The NUT holds a one-day national strike over pay. Strike ballot data suggests the NASUWT may have overtaken the NUT for the number of members actually teaching in schools.
LOSING THE `ZEST OF LIFE'
Changing TES views on union Easter conferences .
31 March, 1923
"It is a specially happy plan that so many teachers hold their annual gatherings during Easter week. The trying winter months, with their cold and darkness, are giving way before spring's warm glow and fresh colours.
"At these conferences we feel as if we have escaped from narrow circumstances to larger liberty, and are ready to enjoy our fellowship of freedom in the frank interchange of experience and the requickening of ideals.
"The season makes its appeal to our bodies and to our minds: the thrill which runs through nature quickens us to a sense of renewed vigour. The zest of life is ours. It is at such a time that we are most likely to take large and higher views of our work. So far as the new life of Easter is allowed free course, our conferences cannot fail to encourage and inspire all who attend them."
21 April, 1995
"Seeing the straggling crocodile of NUT delegates along Blackpool's Golden Mile, Gore Vidal's maxim that anybody who actually wants to become President of the United States should automatically be disqualified comes to mind.
"Surely there must be something wrong with someone who wants to spend Easter in a rain-swept coastal town playing tin soldiers with the union's executive, when the rest of their classroom colleagues have hightailed it to Brittany.
"Perhaps (NUT general secretary) Doug McAvoy should borrow a National Lottery machine. Then if your NUT membership comes up as the numbered balls you are the lucky person to be sent to next year's conference.
"The only disadvantage of that system is it takes at least five years of attending NUT conferences to have the slightest idea what is going on."
Original headline: Eyes on the fight