Every cigarette decreases life expectancy by 20 mins

You've probably heard the anti-smoking campaign line "every cigarette is doing you damage" — but just how bad is a single cigarette for your health? A new study from University College London shows that on average, every single cigarette shortens a smoker's life expectancy by 20 minutes.  Guest: Dr Sarah Jackson, Principal Research Fellow in the UCL Alcohol and Tobacco Research Group Producer: Richard Crabtree