FACE, the Fight Against Cuts in Education, which is organising the protest, appears to have tapped into a deep seam of resentment among parents who are seeing the effect of cuts in their children's schools, where class sizes are rising as a result of teacher job losses.
FACE has its roots in the shire counties. It has mobilised the middle classes in lengthy and frequent protests outside county halls. It has organised doorstep lobbies of candidates in district council elections and attracted families with toddlers in pushchairs to demonstrate in London in March.
Its protest tomorrow - a march from the Embankment at 1.30pm followed by a rally at 3pm at Hyde Park - is backed by the pro-comprehensive Campaign for State Education, as well as the National Confederation of Parent Teacher Associations, the National Governors' Council and the National Campaign for Nursery Education. The action is also supported by Conservative Parents FACE.
It is a safe bet that the true professionals of the street demonstration - the Socialist Workers' Party - will also be present and will have organised coaches and placards.
The National Union of Teachers has refused nationally to support FACE and claimed that the last march was nothing more than a far-Left stunt. It is thought that some of the union members who jostled Labour's David Blunkett at the NUT conference this year, were members of the pressure group.
Nevertheless, many NUT branches are affiliated to the organisation, whose base is a school in Warwickshire.
The National Association of Schoolmasters Union of Women Teachers is the only teacher union publicly supporting FACE. It has donated Pounds 1,000 and Nigel de Gruchy, its general secretary, will address the rally at Hyde Park.
"Although there are some problems with certain political groups like the SWP that is only a minor part of this campaign and it is a problem we can cope with," said Mr de Gruchy. "Most of the protesters will be sound, well-intentioned people and will be there for the right reasons."
The NUT supports Funding our Children's Future, a campaign run under the auspices of the TUC. This campaign is also backed by the Association of Teachers and Lecturers, Unison, CASE, the National Association of Governors and Managers, the NASUWT, and the NCPTA. However, with several groups now campaigning on funding and class sizes, the danger is that resources will be divided rather than united.
FACE emerged as a pressure group campaigning on class size and funding earlier this year. An e-mail message about cuts flashed around schools in Warwickshire by governors and heads sparked a meeting which drew more than 1,000 people. Co-secretaries of the group are NUT member Bob Jelley, head of St Giles middle school in Exhall, and Seamus Crowe, head of St Francis school in Bedworth and a member of the NAHT.
FACE operates out of St Giles middle with a borrowed computer, answerphone and mobile phone. It has around 600 affiliates and predicts tomorrow's rally will attract between 10,000 to 20,000 people.
Bob Jelley added: "There won't be any problems with the SWP. There will be more placards from parents than anyone else.
"When we went to Hyde Park last time there was one solitary Green anarchist. This is a protest from parents and governors all over the country."