Parents have been urged not to put ham and other smoked, salted or cured meat into their children's lunchboxes to help them reduce the risk of cancer.
The World Cancer Research Fund said parents should act now to stop their children developing a taste for processed meat. Eating too much over decades can raise the risk of bowel cancer, they said.
The UK's Food Standards Agency said processed meat was fine for lunchboxes but should not be eaten "too often".
It is only in recent years that the link between processed meats and bowel cancer in adults has been made, with some estimates suggesting that thousands of cases could be prevented if everyone limited intake to 70g a week - equivalent to three rashers of bacon. Even though the available evidence looks only at adult diets, rather than child diets, the World Cancer Research Fund believes that bad eating habits can start in childhood. It says curing, salting or adding preservatives to meat can introduce carcinogenic substances.
It wants the likes of ham and salami given the chop in favour sandwich-fillers such as chicken, fish or cheese.