One in 10 gives schools four hours of their time a week raising cash or aiding pupils.
SCHOOLS rely on more than pound;10 billion's worth of goodwill every year from volunteers.
The National Centre for Volunteering estimates that 6 million people - almost a tenth of the UK population - spends on average four hours a week supporting children's education. They include governors, volunteers hearing children read or working in nurseries, parent-teacher association members and helpers at fetes and sports activities. They contribute pound;10 billion worth of work based on a national average wage of pound;10 an hour.
Another report later this year is expected to find that parents and parent-teacher associations contribute about pound;150 million to state school budgets in covenants, contributions and fund-raising.
The survey has been commissioned by the National Confederation of Parent Teacher Associations and Margaret Morrissey, its spokeswoman, said:
"Expectations of schools have changed out of recognition. They now rely on parents to provide money for curriculum materials and teachers."
A further report from the national charity CSV, in association with the left-leaning think-tank Demos, predicts volunteers will play a greater role in future.
Giving Time suggests that within 10 years they will be involved in citizenship education, mentoring, fighting social exclusion and helping disillusioned youngsters towards learning.
The report redicts volunteering will be a key part of most people's lives and will become a major force to bind communities.
The findings update its 1997 survey of volunteering which found women three times as likely to volunteer in education as men.
CSV estimates 17,000 parent-teacher associations involve 64,000 people giving nearly seven million hours annually, worth nearly pound;70m. It also estimates the UK's 345,000 unpaid school governors give more than 62 million hours worth more than pound;6bn.
But teachers' leaders stressed that goodwill must not be used as an excuse to cut corners or as a substitute for paid professionals.
Jeff Holman, of the National Association of Head Teachers' education department, said: "There has been a long tradition of people helping out in schools and many simply could not survive without them. We recognise and welcome the incredibly valuable contribution they make but stress it should be extra and not to replace paid staff."
Chris Gale, chair of the National Governors' Council, said the long hours and training needed by governors may require that, at least, the chair of governors be paid.
Volunteer Reading Help, which has trained more than 2,000 volunteers in England to help primary school children read, hopes to increase its members four-fold in the next five years. Heather Brandon, VRH director, said: "As well as lifting the reading age we are helping the child gain confidence and fluency."