The relationship between the two was first established in 1950 by scientists in the UK and the US, at precisely the same time that studies revealed that incidences of lung cancer in the US had increased threefold in the previous 30 years.

Before those scientists proved the link definitively, there had been suspicions that smoking caused cancer, but these had been easily countered by the tobacco companies, who regularly used doctors in their advertising. One ad for Camel cigarettes, which is reprinted in a new book called The Cigarette Century by Allan M Brandt, features a benign looking doctor alongside the message: "Give your throat a vacation".

In another, an older doctor, no less trustworthy judging by his unthreatening smile, is depicted holding a pack of Lucky Strikes.

"20,679 Physicians say 'Luckies Are Less Irritating', " the ad proclaims.

These ads, designed to counteract a growing scientific consensus, were supported by other advertising which concentrated on the fun side of smoking. One ad, for Chesterfield cigarettes, showed six stars of the Alfred Hitchcock movie The Paradine Case . . . Gregory Peck, Charles Coburn and Ethel Barrymore amongst them - holding cigarettes, in poses designed to look sexy and sophisticated.

Another ad . . . Lucky Strikes again . . . put smoking in the context of female emancipation.

"Women! Light another torch of freedom. Fight another sex taboo."

Despite the evidence that cigarettes were a killer, smoking rates continued to increase through the 1950s and 1960s. The ubiquitous advertising was only part of the reason. The Cigarette Century makes clear that the tobacco companies put the most enormous efforts into challenging the science and making people believe that the connections between smoking and disease were tenuous. As the US writer Helen Epstein, whose mother Barbara died of lung cancer last year, wrote recently in The New York Review Of Books: "fit seems that the cigarette manufacturers colluded in a highly successful campaign of half-truths and outright falsehoods intended to cast doubt on the lung cancer studies and other research findings. This gave many people the impression that the habit could not be all that dangerous if there was so much 'controversy' about it."

One of Big Tobacco's ruses was the establishment in 1953 of a group called the Tobacco Industry Research Committee (TIRC), which spent the next few years questioning the science and funding scientists who were prepared to doubt publicly the links between smoking and cancer. When some of TIRC's bought-and-paid-for scientists came to the inevitable view that cigarette smoke contained carcinogens, their results were suppressed.

TIRC issued regular bulletins on its findings. "The problem of causation of any type of cancer is complex and difficult to analyse, " it said in a 1957 report. "Despite all the attention given to smoking as an accused factor in human lung cancer, no one has established that cigarette smoke, or any one of its known constituents, is cancer-causing to man". People continued to smoke and die in their tens of millions. Only in recent years, thanks to a combination of high-profile court cases, strict regulation, higher cigarette taxes and smoking bans like the one introduced by Micheal Martin in this country, have the numbers of people smoking around the world decreased substantially. The tobacco companies have responded to this loss of custom by turning their attention to teenagers in the developing world, where 82% of smokers now live, and where glossy advertising for the joy and glamour of cigarettes are widespread.

Efforts to discredit the link between smoking (particularly passive smoking) and cancer continue, most noticeably on a website called www. junkscience. com, which has also become very vigorous recently on the subject of climate change. It is run by a man called Stephen Milloy, who has been lucratively funded over the years by both the tobacco company Philip Morris and the oil company Exxon, which has an obvious vested interest in denying that climate change is a problem for the world. Milloy's mission is to discredit science and scientists who keep coming up with pesky findings which, if they were to win acceptance, would badly hamper the abilities of his benefactors to do business and make money.

The parallels between the climate change deniers and the smoking boosters are astonishing. In both areas, valid, properly researched and peer-reviewed studies identified that there was a problem. In both areas, those studies were challenged by vested interests vigorously enough for the general public to conclude that there must be some "controversy" about the facts. For TIRC in the 1950s, we have junkscience. com today. For all those people who continued to smoke in the 1950s because they saw Gregory Peck waving a cigarette on a poster, we have all those people today who believe that global warming, if it exists at all, will bring as many benefits as problems. For the millions who died from lung cancer in the 1950s, we have the millions in danger now from the increasingly vicious and unforgiving effects of climate change.

The difference is that it is not too late to address the problem of climate change, to reject the purchased opinions of the professional sceptics, and to look for innovative solutions to a crisis that threatens the world as we know it. That can be done by accepting the science, which is as convincing in relation to climate change as it ever was in relation to smoking and lung cancer.

It can also be done by rejecting the notion that there is any serious dispute about the facts and by checking on the bona fides of those people who suggest that there is a genuine controversy. These latter-day holocaust deniers are often funded by vested interests or are journalists with a professional interest in controversy and dispute.

For the moment, by creating confusion and doubt about the facts and thereby delaying the required worldwide response, they are winning, just as the tobacco companies won many years ago. How much longer can they get away with it?