Why is teaching the most unionised job?
Why is education the most unionised jobs sector in the UK?
More than transport, energy, health or mining, education has the highest level of union membership, according to the most recent government figures.
And teachers, gathering over the Easter weekend for their annual conferences, still have remarkably high levels of union membership, bucking trends of declining membership in other parts of the workforce.
The most recent government-commissioned research found 97% of teachers in England belonged to a union.
It's going to feel like the most unionised profession in the next few days, as the National Union of Teachers (NUT) and the National Association of Schoolmasters Union of Women Teachers (Nasuwt) bang their drums.
Expect strike threats, exasperated attacks on education policy and warnings about workload. It's one of the few professions that would give up an entire bank holiday weekend to complain about excessive hours.
In return union leaders will be accused of being dinosaurs and discrediting the profession.
It's such an annual ritual that it's remarkable the card shops haven't got a greetings card for it yet.
Bucking the trend
But what's often overlooked is how much teaching has remained a unionised workplace.
According to the National Foundation for Educational Research (NFER), which carried out the study for the Department for Education, only 3% of staff were not in a union. This was the case for both classroom teachers and senior staff.
That research was published in 2013 and hasn't been repeated, but there is no reason to think much will have changed.
Such near-universal levels of union membership are completely unlike other employment sectors.
Across the UK, about 26% of employees are trade union members, according to the most recent annual survey from the Department for Business, Innovation and Skills.
It's fallen from 32% in the mid-1990s and the current total number of people in unions is about half the peak levels of membership in the late 1970s.
But in education, there are more people in trade unions than a decade ago.
Donkey jackets to tweed jackets
So why have teachers become the torch bearers for the union movement?
Part of the reason might be that trade unionism itself is changing.
Forget 1980s stereotypes of industrial workers around burning braziers. Union membership is now higher among graduates, people in professional jobs, women, middle-income earners and those working in the public sector. It overlaps quite precisely with the typical teacher. It's a better fit for tweed jackets than donkey jackets.
The NFER study asked teachers why they had joined a union and by far the most popular response was "support if there was a problem at work", cited by 72% of teachers. Pay was only mentioned by 1%.
This finding was echoed by Brian Lightman, head of the Association of School and College Leaders, who said "protection and support in case they have difficulties or allegations are made against them" was one of the key drivers for teachers to join a union.
This was also mentioned by Christine Blower, head of the NUT, who said "teachers value the individual support unions provide should any allegations arise".
Lack of trust
It's interesting that teachers feel so vulnerable and expect to have to rely on the protection of their own organisations.
A characteristic of the teachers' conferences is how much the teaching profession seems to distrust the bodies in charge of education, whether it's the Department for Education or Ofsted.
It's as if no-one else really understands how they work or could be relied upon to represent them.
"Unions in education have long had to fulfil the role of professional bodies, offering advice, training and a sense of professional identity often lacking in a system plagued by well-meaning interference from above," said Russell Hobby, leader of the National Association of Head Teachers.
The NUT leader also highlights this dual function that means that teachers' unions have operated as "professional associations as well as trade unions".
Chris Keates, leader of the Nasuwt, says teachers' unions combine "democratic structures" with professional services and training, providing "support when needed for them as individuals or collectively".
These descriptions of the year-round work of teachers' unions are a long way from the fire and brimstone of the conference season.
Teaching is a collegiate, sometimes clannish profession, and conference speeches often show their irritation at the opportunistic interventions of politicians, annoyed that everyone else seems to know better how to do their job.
The conferences are a microcosm of the gulf. Even though the two unions meeting at the weekend will represent about two thirds of the teaching profession, there will be no ministers speaking to them.
The last education secretary to address the National Union of Teachers' conference was Labour's Estelle Morris in 2002, who after being heckled said: "If I told them that tomorrow was Sunday, I think they'd say it wasn't and pass a motion against it."
But how does such a strong union culture change the politics of education? Do the protests change policy?
Jonathan Simons, head of education for the right-wing think tank Policy Exchange, says he expects more "sound and fury" from the conferences - but not enough to dissuade ministers.
"It doesn't actually tend to result in specific change being blocked, if you think of the last series of teacher strikes on pay and pension reform, the reforms are all still happening."
He also argues that protection for teachers' pay isn't driven by the unions, but by the competitive forces of a graduate job in which staff are in relatively high demand.
It's not just the UK where teaching has become the strongest bastion of trade unionism.
John Bangs, senior consultant to Education International, the international umbrella group for teachers' unions, says: "The most unionised workforce in the world is the teaching profession."
Speaking at the recent Global Education and Skills Forum, he told education leaders they had to "get over the fact" that teachers wanted to belong to unions.
The challenge for governments, he said, was: "How can you make that positive rather than a dogfight?".