New research in the UK suggests that it takes just one cigarette as a child to create the adult habit which so many find hard to kick.
In a study funded by Cancer Research UK it was found that trying cigarettes as a child made it twice as likely that a person would take up smoking.
The study on tobacco control, is the first to find a smoking "sleeper effect" - where desire remains years after the first cigarette and has encouraged Cancer Research UK to recommend that anti-smoking campaigns should focus on preventing children trying even one cigarette.
The researchers advise that prevention messages should also be targeted at children while they are still at primary school.
Two thousand young people in 36 London schools were surveyed every year from the age of 11 to 16 for the study and it was found that as many as 14% of 11-year olds and 62% of 15-year olds had smoked a cigarette.
It was revealed that 12% of 11-12 year olds who admitted smoking just once were more likely to take up smoking when they were older compared with those who had never smoked, even after a gap of up to three years of not smoking.
This is the first study that shows an early experience with one cigarette leads to smoking several years in the future.