The Department of Health have kick started their 2013 stop smoking campaign with a rather graphic illustration suggesting your body creates a mutation with every 15 cigarettes you smoke. Mutations can happen by chance when new cells are made as part of normal development or they can be caused by things such as the chemicals in cigarettes that damage the DNA.
The problem is that smokers tend to underestimate their risk and also think of the risks and benefits as being far in the future. This campaign has been designed to show smokers how every extra cigarette adds to the risk of cancer. To watch the video (it is rather gruesome but should hit home the dangers) click on this link.