Inside the restricted laboratory compound on the south coast of England, five senior scientists for BAT Industries, the world's second-biggest cigarette maker, were devising ways to make it harder for people to quit smoking.

At the start of the "brainstorming" session on 11 April 1980, Dr Robin A Crellin, the team research leader, offered an insight. "BAT should learn to look at itself as a drug company," he said, "rather than a tobacco company."

Just eight months earlier, BAT scientists had laid out some basic assumptions about cigarettes. A 28 Aug 1979 memo reads: "We are searching explicitly for a socially acceptable addictive product involving: a pattern of repeated consumption; a product which is likely to involve repeated handling; the essential constituent is most likely to be nicotine or a `direct' substitute for it."

Public disclosure of once-secret industry documents has shown that Big Tobacco privately considered tobacco addictive and harmful at least four . . . [Full text of this article]