Okay, so I did a bit of research and finally found something. If you try a search using "British Tobacco Purity Laws", you will find nothing. In Britain, laws are Acts. And the purity acts aren't exactly what you would expect. They go back as far as the Reign of Charles II and follow up at least through the reign of George II. There may be later permutations, but I didn't have the time to further waste. One of you can do that by performing a worldcat search, using British Tobacco Act as three keywords in an advanced search. If you want to read the actual documents you will have to go to a university whose library collections include copies of this material, or contact the Barrister of your choosing, but I could read the basic points through worldcat. Essentially, the Acts were made to stop the adulteration of tobaccos being shipped from the Americas, wherein they cited adulteration by such foreign material as "floor sweepings" etc which were used to increase the apparent weight of the shipments. There was other chicanery mentioned as well, but the basic point is that tobacco should be comprised of tobacco, not dirt, lint, other crops, etc.
