They are definitely not institutions for the benefit of the poor, contrary to the contribution from Roger Dancey, chief master of King Edward's day school for boys in Birmingham. Mr Dancey devotes much effort to disguising this behind talk of "thrifty" or "lucky" parents who "struggle", find it "difficult to afford" and make "considerable sacrifices", with the further implication that state school parents are incorrigible spendthrifts, sacrificing nothing for their children.
Last week the Office of Fair Trading found that leading independent schools swapped information on fees, resulting in parents being overcharged. This goes to show that the better off, who can ride such increases, are their main customers.
Mr Dancey says that around 15 per cent of his pupils are on bursaries (the national average is 8 per cent); this still leaves 85 per cent (or 92 per cent across the private sector) whose parents can afford the full fees. His contention that "poor" bursary children create "a healthy, socially mixed, multicultural school" is nonsense, as is the argument that private schools are "part of the machinery of social mobility". He contradicts his claim of "open access" by stressing that these lucky children are "bright - very talented", hardly socially representative.
The truth is that the majority of "the poor" are not welcome; bursaries, scholarships, assisted places and vouchers are simply ways of buying other schools' pupils, to boost examination results.
This carefully chosen intake (about 33 per cent of the top quartile nationally) has access to vastly superior resources. So much more can be done if you have 100 teachers for a secondary school of 1,000, rather than 55, and are raking in around pound;20,000 per child a year as opposed to the pound;4,000 per child that state schools receive. But this is "nothing to do with profligacy"! No wonder nine out of 10 private pupils go to university, or to lucrative careers. Despite this, research shows that able children do better in non-selective schools and get better degrees. Such schools only appear to do less well because they enter more pupils, across the whole ability range.
This is luxury education for the more prosperous in our society. There is nothing charitable about it. Suggesting that awards to press-gang able children justifies charitable status is outrageous and brings the notion of charity itself into disrepute. These, alongside "partnerships" with state schools offered by some of the larger private schools, still represent peripheral expenditure, well under 5 per cent of total funding for the feepayers, and have little effect on the schools' raison d'etre. They are equivalent to the goodwill expenditure made by any business (whose fiscal rules private schools think should not apply to them). At best they should attract tax relief, no more; they cannot justify charitable status. "Public benefit" should be available to the public, not just a minority.
And what of the oft-repeated claim that the state is "saved" pound;2 billion? How is this figure justified? The pound;300 million spent on bursaries and scholarships, if included, is money used to rob the state sector. Another pound;100 million is refunded, from charitable status. Is the cost of training their numerous teachers, denied to the state sector by enhanced salaries and better working conditions, included? Is the pound;280 million from the growing number of overseas pupils abroad counted? And what of the more intangible but very real costs, such as the loss to the community's schools of the contribution of those families drawn into the private sector?
Private schools undermine democratically agreed comprehensive systems, and consolidate privilege and thus the inequalities in our society. Can any sum compensate for their divisiveness?
Tony Mitchell is vice-chair of the Socialist Education Association