Tesco launched its Computers for Schools scheme in 1992. Since then schools have used vouchers collected by parents and others to acquire technology worth Pounds 34 million. The company also provides information and communications technology training for teachers.
Most big supermarket chains now run similar schemes for a few months each year. Asda, like Tesco, offers computers and software in exchange for vouchers, while under the Sainsbury's scheme, schools can swap reward points for items including sports, music and science equipment.
Sainsbury's also differentiates its scheme from those of competitors' by recording reward points electronically instead of asking shoppers to collect vouchers.
Other retailers have homed in on under-funded curriculum areas. The Co-op recently repeated its Music for Schools campaign, which the first time round drew in more than 9,000 schools. Between them they exchanged vouchers for instruments worth a total of Pounds 3.2m.
Co-operative Retail Services ran a similar Sports Equipment for Schools scheme from October 1997 to February this year. Market research had found that only 17 per cent of schools were happy with their funding and 85 per cent were interested in a voucher scheme.
"It was this plea for help that convinced us to run the scheme," said Tim Marsden, the national marketing manager for CRS.
But neither retailers nor manufacturers such as Jacob's Bakery, which has also jumped on the reward scheme bandwagon, are donating equipment to schools out of the goodness of their hearts.
A survey by the education charity, Business in the Community, came up with the not very surprising finding that reward schemes are good for business. A majority of the 450 companies surveyed said schemes that benefited education and other causes raised brand awareness and led to increased sales. Most expected "cause-related marketing", as it is known, to grow in importance over the next few years.
Business in the Community, which promotes this type of marketing, also found that 86 per cent of consumers agree that when price and quality are equal, they are more likely to buy a product associated with a cause than one that is not.
There is unease in some quarters about the way schools have come to depend on commercial organisations to provide not only "extras" but also essential equipment - though much of the initial opposition has now given way to resignation.
Margaret Morrissey, of the National Confederation of Parent Teacher Associations, says: "Unfortunately, financial pressures have pushed schools into a situation where they have not been able to afford the luxury of saying: 'This is not right.'" Her confederation is trying to live with reward schemes, she adds, but keeps an eye out for attempts to put pressure on children - for example, by giving prizes to the class that collects the most vouchers or reward points.
One of the confederation's other concerns is that these schemes are magnifying inequalities in the system by favouring larger schools. Certainly, a small school in a rural area would have a hard time collecting the 70, 000 Jacob's biscuit wrappers needed for a piano, though it might manage 250 wrappers for a descant recorder, or even 650 for an If You Ever Meet a Dinosaur songbook and cassette tape. Similarly, with shoppers receiving one voucher for every Pounds 10 they spend at a Tesco store or petrol station, only the largest schools are likely to collect 45,000 vouchers for a library Intranet system.
Guidelines drawn up by a working party of the National Consumer Council say voucher schemes and other marketing activities should enable as many schools as possible to take part - whatever their size or location.
The guidelines also frown on schemes that explicitly encourage shoppers to buy particular brands of goods or encourage children to pester their parents to buy a specific company's products.
A checklist for teachers, governors and parents urges them to consider whether children and teachers can participate in an activity without buying the sponsor's products and whether the activity "is free of incentives to children to eat an unhealthy diet".
The guidelines are supposed to promote good practice. But the National Consumer Council reveals the ambiguity surrounding the issue by declaring that the breach of one guideline does not necessarily mean a sponsored activity falls below standard.
Despite what the guidelines say about promoting particular brands, Asda earlier this year ran a Computers for Kids scheme offering a bonus voucher with some of its own-brand products, while Tesco gave out extra vouchers with packs of Coca-Cola.
Sue Adkins,of Business in the Community, dismisses suggestions that this kind of offer encourages children to pester their parents to buy particular brands of food and drink.
"I think the key point for any of these types of activities is that the communication is with parents and with adults," she says. "It's not about buying extra products. It's about saying you are going to eat and drink anyway, and there's a range of products you can buy or not buy. You make the decision. "
ONE SCHOOL'S EXPERIENCE PARTNERSHIP BENEFITS BOTH SIDES
A primary school in St Albans, Hertfordshire, has devised a novel way of upgrading its computer equipment. Under a scheme devised by How Wood school's information technology co-ordinator Andrew Freeman, a local computer supplier, Systems, Peripherals and Solutions Ltd (SPS), will give the school a credit note worth 7.5 per cent of any sale made to parents, governors or staff. How Wood will be able to use the notes straight away or save them until it has built up enough credit to buy a large piece of equipment from SPS, which has also given the school a multimedia PC.
"The aim was not only to benefit the school, but to make parents aware of the importance of IT and how it is being promoted within schools," says Mr Freeman. He describes the deal with SPS as a partnership which benefits both parties.
Before the launch of this scheme in May, the 220-pupil school had already acquired a computer with reward points from Sainsbury's. It has recently raised enough points for another machine that will be dedicated to the Internet.
"IT is an expensive subject to maintain, and I don't think we would have been able to get these computers without the schemes," says Andrew Freeman."The budget doesn't stretch that far."