The absence of any national guidelines on schools'
involvement with external commercial organisations led to two motions in the Scottish Parliament this year calling on the Executive to "protect children from the promotion of brand names and commercial companies through sponsorship and advertising in Scotland's schools".
MSP Mark Ballard, of the Green party, says the impetus for the motions was an approach by parents in his Lothians constituency who were upset about a school sports day being sponsored by Adidas. "Since they were trying to persuade their kids they didn't need expensive brand-name shoes every Christmas, the last thing they wanted was a school sports day sponsored by a brand."
Having lodged the motions, with the aim of initiating debate in the parliament, proposing action and generating support, Mr Ballard carried out a study into how Scotland's education authorities deal with sponsorship and advertising in schools.
"I found huge variations," he says. "A few authorities, such as North Lanarkshire and Moray, take a very pro-active stance and have developed quite strict guidelines. Some authorities have guidelines that are rather weak.
"Surprisingly, around half our education authorities have no guidelines at all and leave decisions entirely to parent-teacher associations, headteachers and class teachers.
"Now I'm pursuing the possibility of a Private Member's Bill to set up a regulatory framework for the use of sponsored material, such as educational resources or school sports days in schools, or pure advertising material such as vending machines."
Concerns go wider than carbonated drinks and chocolate bars, whose high profile and obvious conflict with the healthy eating message make them easy targets.
"Parents are very concerned about the extent to which schools increasingly rely on resources produced by a particular commercial - or indeed voluntary sector -interest," says Mr Ballard.
"Without guidelines, the PTAs, headteachers and teachers have to make complicated judgment-calls about the educational value of any business involvement.
"Unless we want an American-style free-for-all in Scotland's schools, we need to draw up guidelines and set limits now."
* Soft drink sales in Britain are rising every year. In 2003 an estimated 12.5 billion litres of soft drinks were sold, with a retail value of pound;11 billion
* Sales of soft drinks overtook carbonated drinks in 1998 and continue to grow more rapidly
* Bottled water is one of the fastest growth areas, with sales growing at 13.4 per cent a year
* Sales of low calorie drinks are also on the rise: low calorie colas account for 40 per cent of all cola sales now
* Coca-Cola and Masterfoods (whose machines vend Mars Bars and other confectionery) are reported to have 2,000 and 1,200 vending machines, respectively, in UK secondary schools