An apple a day not only keeps the doctor away, but also improves children's behaviour and academic performance in school, according to headteacher Peter Cansell.

He told a high-powered Parliamentary group, including horticulture minister Lord Whitty, that many of the health benefits of fruit were also greatly increased when children eat raw vegetables.

At Harwell Primary School, children snack on raw swede and mange tout as well as apples and bananas at break time. Harwell was among the first schools in England where pupils were used as guinea pigs by researchers to see how children's eating habits could be improved with more fruit and veg.

As a result, the Government is embarking on radical proposals to improve the health of the nation by launching a scheme to provide most primary school children with a daily ration of fresh fruit.

It will be the first time the Government has positively intervened in the diet of young children since free school milk was withdrawn.

Mr Cansell said he and colleagues at Harwell had previously been concerned that many of the children were snacking on crisps and chocolate, and that as teachers they had a responsibility to help pupils understand the benefits of healthy eating.

So he volunteered the school for a pilot project for a research team from Bangor University whose researchers used a system of "bribes" and incentives as well as education to encourage the children to eat fruit and raw vegetables at break time and lunchtime. The psychological programme was carefully monitored and Mr Cansell said the experiment quickly resulted in positive benefits.