The makers of two of Britain's best-selling soft drinks, Lucozade and Irn-Bru, have been forced to warn parents that the drinks may cause hyperactivity.
A newly introduced EU law compels both drinks to display a warning that they contain artificial colours linked to behavioural problems in young children.
Manufacturers were asked to remove the colours two years ago by the Food Standards Agency (FSA) following a study which found they worsened the behaviour of young children. Lucozade Original's lurid yellow appearance comes from sunset yellow, or E110, while Irn-Bru's distinctive orange glow comes from sunset yellow and a red colouring, ponceau 4R (E124).
Both also contain sodium benzoate (E211), a preservative that was found to cause hyperactivity by Southampton University, but which is not covered by the EU rule. Lucozade's owner GlaxoSmithKline warned shoppers about sunset yellow voluntarily, but it and Irn-Bru's maker AG Barr have to state that the additives "may have effects on activity and attention in children".
Jackie Schneider, of the Children's Food Campaign, said: "I can't imagine a good reason why they are using these additives. [The drinks] don't seem to be marketed at children but they are linked to sporting activities."