Back in 1896 tobacco was heralded as an effective way of preventing disease.
We know different now, but it wasn't until 1954 that a Medical Research Council study by Sir Richard Doll and Sir Austin Bradford Hill showed a link between smoking and lung cancer.
At a news conference in 1954, reporting this first link between smoking and cancer, Health Minister Iain McLeod chain smoked throughout!
By 2013 the proportion of adults smoking in the UK had declined to its lowest level since recording started in the 1940s, with official figures suggesting that the habit's prevalence among over-18s fell from 19.8% in 2012 to 18.7% in 2013 - aided by Public Health SmokeFree Services like this http://www.nhs.uk/smokefree#eXLf5e4R0E8CScem.97
and that's a fact!