Bee Wilson on the hellish "Dairylea Lunchables"

Chuck out the crisps and chocolate, and the kids behave better

If there is one product guaranteed to unite middle-class mums in pious horror, it is Sunny Delight - the evil-looking, additive-laden, sugary beverage, notorious for having once turned a child who drank too much of it orange. We train up our progeny early to despise its bright labels and false promise. My three-year-old son shudders theatrically when he spots it being advertised and chants "Sunny Deeee" in the same doom-laden tones that children of earlier years saved for "The Devil".

But now, though it feels like heresy to admit it, I've decided that Sunny Delight is not the most hellish foodstuff aimed at children. That honour belongs to "Dairylea Lunchables", a complete children's lunch in a plastic container which fails to satisfy any of the qualities associated with lunch. Taste, pleasure and health are all absent. They should be called "unlunchables". For £1.45 you get three depressing compartments filled with "golden crackers", a stack of cheese food slices and a stack of "formed ham" circles, with the texture of predigested gristle. This version is called "Harvest Ham". Even worse is a hot-dog variant ("no need to heat"!) which proposes that a child sustain themselves for the afternoon on three minuscule dextrose-rich frankfurters, three puny walnut-sized white rolls, some cheese food slices ("a good source of calcium") and a sachet of ketchup.

It is foods such as these that prompted New End Primary School in Hampstead, north London, to engage in a daring piece of social engineering. As of September this year, those pupils choosing to bring in a lunch box had to fill it with "healthy" foods. All forms of crisps, chocolate, sweets and junk food were banned. The only drink allowed was water. Fruit and vegetables were encouraged. The headmistress, Pam Fitzpatrick, a very brisk, capable-sounding woman, tells me that the result has been a dramatic improvement in the children's behaviour, with a much "calmer atmosphere" in lessons after lunch.

The New End school council mooted the idea, as much a measure against litter as one to improve the children's diets. Previously, "lots of kids had been bringing in crisps and dropping the packets around". There was also a problem with children "chucking away" the sandwiches from their lunch boxes and eating only the junk. Now, in just three months, the school's litter problem has disappeared.

Surprisingly, there have been almost no violations of the new rules, though Fitzpatrick says she did find one child with a sandwich filled with crisps when she was out "patrolling" one lunchtime. Her policy, when she finds something "slightly untoward" in a lunch box is to explain why it isn't healthy and tell the child not to bring it in again. Fitzpatrick says the general response, from the 50 per cent of pupils who bring in their own lunches, has been positive, and "parents are delighted". One boy ticked off the headmistress when he saw her drinking a cup of tea, commenting that it wasn't fair when he was allowed only water. The school encourages such debate.

Judged by its effects, the New End lunch-box scheme seems admirable. But policing lunches in this way raises questions of liberty as well as personal taste. How do you define a "healthy diet" for children? Fitzpatrick is keen not to encourage eating disorders and anxious to put across a message of balance rather than emaciation. Yet banning foods is not always the best route to balance. For example, because sugar is seen as an enemy at New End, home-made cakes are currently not allowed, though fruit yogurts are. This is rather melancholy.

Personally, I would be happy if children everywhere were forcibly restrained from all contact with Sunny Delight and "Lunchables"; but I would still let them eat cake.