Ms Wood, a teaching assistant, has been given a more important role in children’s education under the workforce remodelling of the past four years. These are roles that most of the community, many parents, and even some teachers, remain largely unaware of.

“We take classes of up to 20 pupils on our own and are paid only at teaching assistant rates,” says Ms Wood, who works at Telscombe Cliffs Primary, Peacehaven in East Sussex. “It’s a bit of an insult really.

“Teachers respect our professionalism. But to really show someone respect you should pay them more than someone who does the nightshift at Asda.”

Angie Butler has heard reports of teaching assistants in some schools being banned from the staffroom. The senior learning assistant works at The Hayfield School in Doncaster, south Yorkshire, where her professionalism is acknowledged. But she says she is still underpaid and has no opportunity to advance. As a senior learning assistant with more than 16 years’ experience, Ms Butler, 56, is paid a tad over pound;10,000 a year for 32 hours a week and is paid for term time only.

A few years ago she had the chance to become a qualified teacher. She was in the middle of a divorce and chose the “safety” of her existing job. But the level of her pay obviously rankles. “I feel that we’re still regarded like good mums who volunteer to come in and help out,” she says. “We have so much training and experience. It’s not used.”

Official statistics this year showed 308,000 full-time equivalent support staff in schools, most of them teaching assistants. But that is literally only half the story. Because so many support staff are working part-time, there are estimated to be up to 600,000 working in schools to support children’s education.

That means there are more support staff in English schools than there are teachers. There are 439,000 full-time equivalent teachers, and far fewer of them work part-time.

Half of English schools have created new, non-teaching cover supervision, behaviour management or pastoral care jobs in the past two years, according to a survey published this week by Select Education, the supply agency.

Yet, after four years of workforce remodelling that has arguably improved teachers’ work-life balance and pay packets, support staff say they are often still treated as second class citizens.

One in five support staff are paid less than pound;9,000 a year. Two-thirds earn less than pound;15,000.

Support staff at local authority maintained schools came to the brink of walking off the job this month when Unison, the biggest local government workers’ union, balloted for strike action over a pay increase offer of 2.475 per cent.

Members voted to strike but because of the low response rate the union’s executive decided to hold fire untill the next pay round in April. The fact that few people know how close our schools came to a walkout is perhaps indicative of the low status of support staff.

Unison, which represents 200,000 of England’s school support staff, has surveyed more than 1,000 members and 200 schools.

Its report, published today, applauds schools which have acknowledged the greater range of responsibilities their support staff have taken on since workforce remodelling by promoting them. Of those support staff affected by the remodelling, two out of five have received a pay rise.

But most schools still employ their teaching assistants and other support staff on term-time contracts, meaning they are paid for only 38 to 44 weeks of the year.

And nearly half the schools that responded were paying higher-level teaching assistant wages only for part of the week and paying those staff lower wages for the rest.

“We want to stamp down hard on this unfair practice,” said Dave Prentis, the union’s general secretary. “We have always argued that the high skills recognised through HLTA status should be rewarded in one contract.”

In a new government-commissioned study on how remodelling has affected schools, George Phipson, a funding consultant, also notes the use of term-only contracts and split contracts. He describes the split contracts as “expressly contradictory” to guidance issued by the government’s Workforce Agreement Monitoring Group.

At the 550-pupil Telscombe Cliffs Primary, there are 18 classes. Every classroom teacher is supported by a teaching assistant.

To allow those 18 teachers their guaranteed preparation time - calculated at two hours a week - a full-time qualified music teacher goes from class to class.

But that covers only half of the time the teachers are guaranteed away from the classroom. The rest of the time, says Ms Wood, the teaching assistants step in and deliver prepared lesson plans.

Some are well-trained - she and two colleagues have completed university courses in working with dyspraxic and dyslexic children. Others have qualified as higher-level teaching assistants, but their pay is skewed: in the mornings (21 hours), they get a lower rate for assisting teachers; in the afternoons (9 hours), they are paid a slightly higher rate for covering classes.

An East Sussex County Council spokesman said schools were allowed flexibility in managing their staffing and budget. “This may mean they choose to use split or hybrid contracts for teaching assistants,” he said.

In April, schools will have to tighten their belts with the arrival of a three-year funding round. About 5,700 schools will get only the bare minimum 2.1 per cent funding increase.

That will inevitably affect staffing - and it will be the jobs of the most vulnerable part-time and temporary workers that are most at risk.

Martin Johnson, acting deputy general secretary of the Association of Teachers and Lecturers, said there was too much bad practice in deployment of support staff.

He said: “They are too often asked to do things for which they are not qualified or trained and they are often not paid the appropriate rate. Headteachers do not always follow the regulations.”