Teenagers are aware of the reasons why they should not smoke, and will happily echo their teachers' warnings about peer pressure and addiction. This does not, however, prevent them from actually smoking.
Fin Cullen, of Brunel University, spent a year-and-a-half talking to 100 pupils, aged between 14 and 19, about their smoking habits. She found that the teenagers took up smoking for a variety of reasons: youthful experimentation, boredom and stress relief.
Many also claimed that they smoked in order to fit in. However, they had internalised the lessons of PSHE lessons, and insisted that they were not victims of peer pressure.
For example, 14-year-old Amy said: "I started smoking cos all my friends were doing it. I might as well do it as well. It wasn't, like, a peer-pressure thing... but just because I thought, 'Hey, all my friends are doing it. I may as well'."
Similarly, 14-year-old Jodie described how a close friend influenced her decision to start smoking, but insisted: "I wasn't pressured or anything. I did it for my own thing."
Friends also influenced which cigarettes teenagers chose to smoke. Middle-class girls tended to smoke Marlboro Lights and tobacco roll-ups. Meanwhile, less-affluent "rudies" and "townies" preferred the Mayfair and Richmond brands. Cigarettes became a badge of identity: "grunger" girls claimed that cheaper cigarettes were "trampy", and saw roll-ups as an indication of their deliberately alternative identity.
In fact, even non-smokers would buy - and then give away - certain brands of cigarettes, using their brand awareness as a way to demonstrate their place in the social hierarchy.
And changing brand was a way to reinforce new friendships. Sixteen-year-old Ella said: "I always used to smoke BH Silver before I met my friends, but they converted me."
The teenagers were all aware of the addictive qualities of nicotine. Jodie, for example, talked about being "proper addicted... If we haven't had a fag in, like, two hours, we literally cry".
She and her friend Lisa, 15, discussed their need to fit their cigarette cravings around the school timetable. "I, like, keep 'em in my pencil-case and I look at them," said Jodie. "And I think, 'just another half an hour'."
And Lisa said: "I just have to hold my pencil just like I'm holding a cigarette. Then I'm fine until breaktime."
This need for cigarettes allowed pupils to wield power over one another. For example, when 17-year-old Sylvia asked her classmate, Sade, if she had a spare cigarette, Sade responded: "There's no such thing as a spare cigarette. It's not like when I bought a 10-pack there was a spare. You can have one, but it's not spare. I intended to smoke it."
Similarly, 14-year-old Noel complained that Lisa owed him 10 cigarettes. However, Noel looked too young to be sold cigarettes. Lisa therefore held the balance of power: he needed her help in order to satisfy his addiction.
"Such bribery was a regular occurrence... with young people imploring friends to accompany them into the cold of the outside smoking area with a promise of a fag," Ms Cullen said.
She added that, if teachers are to tackle teenage smoking successfully, they need greater awareness of the broader symbolic significance of cigarettes.
"If tobacco education and smoking-cessation initiatives are to be more meaningful, then a starting point must be based on young people's own understandings about the social complexities and meanings of substance use within their own networks," she said.
Why and when
'Fine until break'
"I started smoking cos all my friends were doing it. It wasn't a peer-pressure thing... but just because I thought, 'Hey, all my friends are doing it. I may as well'."
"If we haven't had a fag, like, in two hours, we literally cry. Cos, like, at school I have one at half-eight and then I can't have another one till 11.20. And from, like, half 10 I look at the clock and I'm like, 'hurry up'. I, like, keep 'em in my pencil-case and I look at them."
"I just have to hold my pencil just like I'm holding a cigarette. Then I'm fine until breaktime."
"There's no such thing as a spare cigarette. It's not like when I bought a 10-pack there was a spare. You can have one, but it's not spare. I intended to smoke it."