Cadbury, manufacturer of Dairy Milk, Creme Eggs and other delicious treats, has found a new way of delighting our children. As the Observer reveals today, the company is to launch a nationwide scheme to encourage pupils to buy their chocolate bars in order to 'earn' free sports equipment for schools.

Cause-related marketing, as it is known, has been around for years. Walker's Crisps has provided books for schools, and Tesco vouchers gave headteachers desperately needed computers. But linking the eating of any product such as chocolate, rich in fat and sugar, to physical fitness is different. The 'big-hearted' confectioner, as it styles itself, claims that it isn't chocolate that makes you fat, it's lack of exercise. Obesity is certainly caused by a complex relationship between diet and activity, but there is a clear link between junk food and extra pounds. After eating a bar of Dairy Milk, you would need to take a brisk three-mile walk to burn off its calories. How many children do that?

That ministers are stepping over each other to back the £9 million scheme has raised the hackles of teachers and healthcare staff who have to deal with the consequences of obesity. A child who is overweight is likely to be bullied and develop heart disease, diabetes and a range of other life-shortening illnesses.

TV advertising during the daytime is already strictly regulated precisely because there is extensive evidence that children are easily impressionable. A code of conduct setting out rules over the promotion of food and drinks to children is the minimum that is now needed from ministers to prevent such inappropriate campaigns in future. If companies such as Cadbury genuinely want to make the nation fitter, they could supply £9m of badly needed sports equipment to schools without linking it to chocolate sales.