Scientific research has revealed that unhealthy school dinners are partly responsible for pupils' bad behaviour in schools.

Dr Neil Ward of Surrey University has revealed that too much sugar and a lack of zinc and iron in school meals is causing anti social behaviour in the classroom.

And by improving the quality of school meals, there would be less need for children with Hyperactivity Disorder to take the prescription drug Ritalin.

He joined the Soil Association in putting pressure on the Education Secretary Charles Clarke to improve the quality of school meals.

Mr Clarke has said his department will be monitoring the quality of school meals.