The company, Imagination for School Media Marketing, based in Leigh-on-Sea, Essex, denies it is taking advantage of cash-strapped schools.
Some 380 secondary schools have signed up for the scheme which will put 10 billboards in their buildings. Each will earn 35 per cent of the gross revenue from the advertising, - just over pound;5,000-a-year if all the 6ft-high hoardings are filled for the whole academic year.
The first hoardings in a nationwide campaign will go up in April and a further 600 schools have expressed an interest.
The plan was condemned in the national press when it was first put forward in 1996. "I can still see the headline in my nightmares," says marketing manager Mike Wilsher. "It said burgers and trainers to be sold to our kids in schools."
But he says heads have been keen to sign up - as have advertisers. "I can't give you names I'm afraid, but I can give you sectors. Certainly film releases, music releases, retailers. Also the sort of people who are interested are anti-drugs and anti-smoking campaigners."
He said care has been taken over what can be advertised in what he admits is a "sensitive area", and ads will not be allowed in the classroom. "We would not allow things like sugary fizzy drinks. We wouldn't entertain computer games or sportswear, or selected confectionary. But if let's say Cadbury's came up with an anti-litter campaign, then we'd certainly look at it. We toe the National Consumer Council guidelines on advertising and sponsorship in schools. And the head does have the final veto.
"I'm a parent and I know there's a cash crisis in schools - you don't have to be a genius to know that. However, I don't think we're putting them under any pressure."
Sandfields comprehensive in Port Talbot, is one of 26 schools to sign up in Wales. The 607-pupil school already has a separate scheme where certificates for hard work can be exchanged for a pound;5 McDonald's voucher but there was still much soul-searching over whether to agree to ad hoardings, said deputy head John Richards.
"In the great scheme of things pound;5,000 is a drop in the ocean and you've got to make certain that we do get value for money, that it's not counter-productive and that it doesn't work against the image of the school.
Nigel de Gruchy, general secretary of the National Association of Schoolmasters Union of Women Teachers, condemned the use of billboards in schools.
"It is very depressing that schools are forced to raise money in this way. Billboard advertising is a cultural low and they're an obvious target for graffiti, and maybe rightly so. In some ways you couldn't blame the kids for defacing these monstrosities."
In response to ISMM's claim that it toed the National Consumer Council guidelines on advertising and sponsorship, Ruth Evans, the council's director, said the guidelines only covered sponsorship. "Schools should be an advertising-free zone. Children are there to learn. It shouldn't be a market place - they get enough of that outside."