Until now, the BHF has targeted adults with TV and print ads that show fat oozing from smokers' arteries.
The move online will see the launch of two dedicated websites, developed by Craik Jones Digital, aimed at encouraging young people to reject smoking and lead an active lifestyle.
BHF children's resources manager, Deborah Allen, said: "These two websites are an ideal way of engaging with the audiences of such different ages and interests."
The sites, one targeting teens and the other those aged under 11, will allow children to design on-pack health warnings for cigarettes, take part in a healthy eating quiz and ask an expert questions about their health.
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