The Food Standards Agency has told parents that they should not allow children under seven to drink Slushies, warning of the “serious health risks” posed by high glycerol intake.

Children aged between seven and ten should also be limited to 350ml per day, according to the health body, which urged guardians to look out for E422, or glycerine in ingredients lists.

“While these drinks may seem harmless and side-effects are generally mild, they can, especially when consumed in large quantities over a short time, pose serious health risks to young children,” said FSA chief scientific adviser Professor Robin May.

“We’re working closely with industry to ensure appropriate warnings are in place wherever these drinks are sold, but in the meantime we are asking parents and carers to take extra care when buying drinks for young children.”

The FSA also encouraged retailers not to offer free Slushy refills to children under ten.