While tobacco companies have been forced to spend millions by courts on anti-smoking advertising campaigns, they have been furtively increasing the nicotine content of cigarettes to keep smokers addicted. According to a study by the Massachusetts Department of Public Health, nicotine in the average cigarette has gone up 10% since 1998. Experts warn that cigarettes with high nicotine content are the easiest to become addicted to and the hardest to stop using.

Link to audio report from the BBC here.