The science of tobacco, tobacco smoke and the exact process by which something or things in tobacco smoke causes, in some cases, illness remains unresolved even today. Tobacco smoke is an incredibly complicated compound. The number of constituents in tobacco smoke was initially estimated to be around 300 by the Royal College of Physicians in 1962, was put at 5,000 in 2011 and 7,000 according to the American Lung Association now. Obviously scientific methods have developed enormously over the last half century, hence the ability to record more compounds but this highlights that the “newer” compounds discovered must be in very small quantities indeed. As highlighted in 2000 in New Zealand (and based on an estimate of 4,000 chemical constituents) “400 have been measured” and “of the 400, a significant amount of toxicology data exist for less than 100”.

How the combinations of factors in smoke interact, over considerable periods of time, remains unproven in science and has proven incredibly difficult to replicate in the laboratory. Originally the aim of scientists, within and out with the tobacco industry, was to isolate “the element” which was possibly, or probably, carcinogenic to humans and to remove it. Unfortunately it has been unclear how to achieve this and, as one scientist in the sector once put it to me, removing just one element may not change the outcome. He chose as an example the removal of one ball from a snooker table. When the pack is hit without that one ball there will be movement still, just that the impact will be different. As we cannot, still, isolate the crucial element removing one interaction could simply create different ones. As the seminal 1962 Royal College of Physicians report “Smoking and health” stated (para 100) “It should be realised that since we cannot identify the substances in tobacco smoke that may be injurious to health, no firm claims for the safety of modified cigarette tobaccos or filters can be made. It would, of course, be many years before it would be possible to detect any effector upon death rates resulting from the use of cigarettes with filter tips, or of modified tobaccos”.

The suggestion is normally made that the industry hid its own research but the tobacco companies in the UK worked with the Government and public health groups, setting up a Standing Committee in 1956 with the mission “To assist research into smoking and health questions, to keep in touch with scientists and other working on this subject in the UK and abroad, and to make information available to scientific workers and the public”. In 1968 America’s National Cancer Institute set up “The Less Hazardous Cigarette Working Group” to investigate the possibility that the health risks of smoking could be reduced. Scientists from the tobacco industry were invited to join, with the only influence exerted by the industry being in the change of name to “The Tobacco Working Group”. The aim at the time was very clearly one of harm reduction.

It is fair to say that various tobacco industry executives called into question the veracity of the suggested links between smoking and ill-health. But they were not alone. The statistical approach adopted by Doll and Hill was challenged by R. A. Fisher with some merit, although he believed cigarettes to be harmless which bears little scrutiny with the passing of time. Dr Charles Mayo, the son of the founder of the Mayo Clinic, said “I just don’t believe smoking causes lung cancer”. In 1957 the Surgeon General of the time, Dr Leroy Burney, was asked “Do you think people should quit smoking?” to which he replied “No, sir, I do not believe they should quit smoking”. Perhaps this was related to his answer to a question in a different interview in which he was asked “What do you mean exactly by ‘excessive and prolonged’? Do you mean a pack of cigarettes a day, two packs, a period of 20 years, or what do you mean by that?” to which he offered the answer “We mean at least two packs a day, or more, and over a period of 20 to 30 years. Now that’s a long while”.

The advice of the RCP in 1962 was that the harmful effect of smoking might be reduced through “efficient filters, by using modified tobaccos, by leaving longer cigarette stubs or by changing from cigarette to pipe or cigar smoking”. So the efforts of the industry to seek modified versions of tobacco, to reduce tar and to explore filtration were not necessarily part of a vast conspiracy but rather consistent reactions to the advice of external experts.