There are an estimated 40,000 union representatives in the UK and Alison manages by honing her organisational skills. “It’s a question of learning to prioritise. I make sure my lessons are all planned for the week by Sunday night, so that side is done and dusted.”

Although she admits that there can be tension involved in having to mediate between employers and colleagues, she doesn’t believe schools see teachers who take on union duties as troublesome.

“There’s the potential for any member of staff to be seen as a troublemaker. But our role is also positive - we can help to nip problems in the bud. So much depends on the relationship with the school. I’m lucky that my school is very supportive and I have a good relationship with senior management. They get the benefit of someone who has knowledge of the latest developments taking place.”

The three biggest unions aim to have at least one representative at each school in the country, responsible for disseminating information about their works, and acting as the first contact point for members who need help.

Routine tasks range from opening union mail, distributing leaflets in the staffroom or putting up posters, to dealing with problems colleagues may be having with school management. A union rep has to balance his or her role as a member of staff, accountable to senior management, with their responsibility to fellow employees as a union official. You have to know when a problem is too complex for you to handle, and who to hand it to.

Among the commonest obstacles are issues of performance management. Reps often provide a sympathetic shoulder for teachers who feel bullied by managers. Their job is to decide whether empathy and support is sufficient, or the reported bullying is severe enough to warrant further action such as confronting the manager, or involving more senior union officials.

One union rep, who wished to remain anonymous, said that when he took on the post, relations between staff and managers at his school were shocking.

“We have a head who is quite difficult. She observes teachers she doesn’t trust repeatedly, making them feel undermined. A colleague came to me in tears, asking my advice.

“I reminded the head that she wasn’t adhering to national guidelines agreed with the unions on frequency of observations. It was difficult because my colleague didn’t want it made clear she’d come to me,” he says.

On another occasion, the rep supported a junior colleague who felt she wasn’t getting the opportunity to attend courses during school-time because, she was told, she couldn’t be spared. “She was frightened to challenge the head and insist on her right to training. I helped her draft a letter stating how she felt, then mediated a meeting between the two of them, which led to a compromise solution,” he says.

Heather Reynolds, who is an English teacher at Prenton High School for Girls in Birkenhead, Merseyside, is hugely enthusiastic about her job as rep for the National Union of Teachers, although she freely admits she is still feeling her way after deciding to take the job on at a course run for NQTs by the union last year. She believes that confrontation is by no means inevitable, but that much depends both on the attitude of the rep and his or her school management.

“I’ve got no axe to grind here. At my first school, it was volatile because the union rep was pretty hardline, but I don’t want to alienate colleagues, it’s important to win people’s trust. I feel quite safe as far as my job goes. I want to make the union more visible at school - to make new staff feel they’ve really got some support.”

John Dixon, the National Union of Teachers’ head of co-ordination, local support and action, says that if there were any suggestion that a union representative was being adversely affected at school because of their union activities, they would be fully protected by the law.

But in the vast majority of cases, he says - and the NUT has almost 20,000 school reps - they are seen as particularly valuable members of staff.

“They are the face of the union in their school, and that’s really important,” he says.

“We appreciate their work, and offer them useful training on topics such as the role of the school rep, how to deal with the head, conflict resolution and negotiation. So it’s a win-win situation.”

How to become a union rep

In theory, to become a union representative for your school you need to be elected by other members, but most often, if you are prepared to volunteer for the job, no ballot is held.

The formal length of office is one year, but unless an objection is raised at the union’s local annual general meeting people can continue as reps for as long as they wish.

Another way in, for teachers who have just qualified, is through one of the NQT introductory courses regularly held by unions.

The course held by the NUT, for example, contains a section explaining how and why to become a union rep, and how to join the young teachers’ panel - which is made up of union representatives under 35 years old.

The work of school representatives is not paid, and is supposed to be carried out in your own time, but it can be minimal - opening post, maintaining the notice board and referring on, if that is all you have time for.