For both the UK and the US, the rules are the same you can bring back a maximum of 200 cigarettes (so one carton, typically) from duty-free, but anything over that you will need to declare at customs and pay tax on
Drugs similar in structure to the target drug may cross-react to produce a non-negative or presumptive positive result
Given their primary goal of maximizing profits, however, it is unlikely, that the tobacco companies will do that on their own, despite all the ethical, moral, and public health reasons that they should. As the cost of cigarettes continues to rise, largely due to increased taxes aimed at discouraging their sale, cigarette companies are relying more and more on coupons to help offset the tax hikes and keep their products affordable
Additionally, tobacco use disproportionately affects lower-income households, with Papua New Guineans in the lowest-income quartile smoking more on average than those in higher-income groups
'Birds of America' is considered a masterpiece of the natural world, printed between 1827 and 1838