Breathing in someone else's smoke is called passive smoking. Some smoke comes straight from the cigarette, some of it is second-hand - recycled when the smoker breathes out.

Every year, about 17,000 children under five go into hospital because their parents smoke - they're more likely to have asthma, bronchitis, pneumonia, and ear infections. Colds and flu last longer. Smokers' babies are more likely to suffer from "colic" (pains that make them wriggle and cry), and there's a higher risk of "cot death".

And the children of smokers are also more likely to become smokers themselves.