The "previous study"
This whole subject was covered in the "The Smoke Screen" episode of Yes, Prime Minister. For a summary of the plot take a look at http://www.yes-minister.com/ypmseas1a.htm#YPM%201.3 - "Humphrey points to the fact that cigarettes produce 4 billion pounds a year in tax revenue. Jim Hacker points out that smoking related diseases cause 100,000 premature deaths a year, but Sir Humphrey argues that otherwise these people would have cost the government financially even more in pensions and social security." and the show was broadcast in 1986.
For those of you who don't know of the show (or have never watched it):
- Maggie Thatcher used to arrange her diary to be able to watch it since she liked its accuracy;
- It was very, very well researched and many stories either had occurred or occurred after an episode was shown(!).