"The clang of a metal pipe against an old car wheel resounded across the schoolyard, signalling the end of morning classes, but none of the 70 students in Kung Vichet's fourth-grade class budged from their seats. Instead, they put away the notes they had been taking on how magnets work and brought out their mathematics notebooks. Private schooling had begun."
This description from a Cambodian government education review shows the extent to which schools that should be free have begun charging for tuition, and represents the hidden costs of public schooling in a number of countries in Asia.
"Private tutoring is not, as one might assume, an opportunity for individual students to get special help on material they did not understand in class," the government review states. "Instead, it constitutes an extension of the regular curriculum, offered by the same teacher in the same large group setting."
Schools in China, Vietnam, Cambodia and Laos that provided free primary education under former socialist systems are now levying so many charges that in some cases the parental contribution outweighs that of the state.
Figures collated by Dr Mark Bray of Hong Kong University for the World Bank study Counting the Full Cost show that in Cambodia where free primary education is enshrined in the constitution, a staggering 75 per cent of the cost of "free" primary schooling is borne by parents.
In China, 20-25 per cent of the cost of state-run primary education is covered by households; in Laos, it is almost 30 per cent. In Vietnam and Cambodia, the household contribution is greater than the state's, amounting to 50 per cent in Vietnam, officially a socialist country where, at least until recently, a strong emphasis was placed on government provision of education.
"What it amounts to is privatised public schooling," says Dr Bray. "There is little choice. They must pay or forfeit education altogether.
"And what is most worrying is that when children are given private tutoring by their regular teachers, an element of blackmail is commonly involved, for some teachers provide only the bare minimum during school hours and reserve the real teaching for their private classes."
For the poorest communities the level of ad hoc contributions is leading directly to high drop-out rates, which defeat the aims of free access to education. It may also contribute to increased poverty among the poorest in countries where primary school was once free, particularly since the poor have more children than the rich.
In Vietnam, which used to boast universal primary school enrolment in the early 1990s, numbers fell sharply as costs to parents rose, so that by 1993 only 78 per cent of children aged six to 10 were enrolled in primary schools.
In China, small rural private tutorial schools funded by the community have sprung up to teach the poorest children whose parents can no longer afford the charges levied in the public schools. So high are the ad hoc charges levied by some state-run schools that some private-tutor schools, known as sishu, are able to provide basic numeracy and literacy at half the cost of normal schooling.
Dr Bray notes that the development of household contributions to free public education is a case of "market forces salvaging a system", which would otherwise be unable to function. In Cambodia, the school system is suffering the effects of abysmal teacher pay and a government falling apart and unable to pay for its schools.
In China and Vietnam, the transition from pure socialism to a more market-orientated system is causing a breakdown in public funding, which in China includes delays of several months in paying teachers in several provinces. In Vietnam, where economic stringency led to the introduction of fees for post-primary schools in 1989, austerity, high inflation and lack of government revenue has led to funding deficiencies at primary level.
In China, officially there is no tuition fee until the end of junior secondary school. Charges, however, are quite blatant and receipts are provided. One receipt to a student includes such items as "desk and chair fee", water and electricity, maintenance of fans, public security, health check-up and funds for teacher retirement.
"Although no tuition fee was demanded, as many as 24 other charges were made," said Dr Bray.
Vietnam and Cambodia are less upfront about charges but they include labour and materials in addition to the ubiquitous mass "private tutoring" by the class teacher.
And yet, says Dr Bray, government ministers still insist that education is free.