Sir Richard Doll, the scientist who first confirmed the link between smoking and lung cancer, has died.
A lifetime of groundbreaking work
Oxford University said the epidemiologist died at the John Radcliffe Hospital, Oxford, after a short illness. He was 92.
One of the world's most highly regarded professors, Sir Richard was responsible for the good health of millions.
His seminal 1950 study, which he wrote with Austin Bradford Hill, said smoking was "a major cause" of lung cancer.
Dr John Hood, Vice-Chancellor of the University of Oxford, said the professor's work had saved millions of lives.
He said: "Sir Richard's enormous contribution to medicine globally, and within Oxford, cannot be understated.
"His pioneering epidemiological work on the link between smoking and cancer, cardiovascular disease and many other disorders, has led to the dramatic reduction in smoking rates in Britain over the past 50 years, especially among men."
Professor Alex Markham, chief executive of Cancer Research UK, said: "There is already one extraordinary memorial to this truly exceptional individual - the millions of lives that he saved through revealing the truth about the deadly nature of smoking."
Medical Research Council Chief Executive, Professor Colin Blakemore, said: "Professor Sir Richard Doll was one of the most important medical scientists of the 20th Century.
"His proof of the link between smoking and cancer has done as much to save lives as the discovery of penicillin or the development of polio vaccine."
Born in London in 1912 to a GP father, Doll took up medical research after failing a maths exam. He qualified from St Thomas's Medical School in 1937, and undertook wartime service with the Royal Army Medical Corps.
After a friend spotted a vacancy at the Medical Research Council, Sir Richard was given the task of discovering why the number of lung cancer diagnoses had risen so sharply.
Sir Richard proved the harm of cigarettes
Initially Sir Richard suspected the cause to be car exhaust fumes, but he soon began to investigate the growing trend of cigarette smoking.
A large number of London hospital patients answered questionnaires, and Sir Richard later described his analysis of the results as the most exciting time of his life.
Data from 600 patients confirmed his latest hunch, and so the professor extended his research to cover the entire country. The results were conclusive.
With Professor Austin Bradford Hill, Sir Richard proved that the risk of lung cancer was directly proportional to the number of cigarettes his patients smoked.
Follow-up studies proved that long-time smokers suffered three times the mortality rate of non-smokers. Sir Richard later affirmed the link between smoking and coronary thrombosis, as well as with at least 18 other serious diseases.
Sir Richard analysed thousands of reports
For his pioneering work, Sir Richard was awarded $10,000 from the World Health Organization and received a knighthood in 1972.
As well as his studies into cancer and heart disease, he investigated the effects of alcohol on unborn babies, and the side effects of the birth control pill.
He claimed to find his work on radiation the most satisfying. Other scientists in the 1950s claimed only large doses of radiation caused human damage.
But Sir Richard proved conclusively that even a small amount of ionising radiation posed a risk of leukaemia and other illness.
Caused a stir
The untiring professor remained a leader in his field of epidemiology, the spread of disease, well into his eighties, when he was awarded the Companion of Honour in 1996.
He caused a stir in 1973, aged 60, by saying that people aged over 65 should be prepared to accept death and not think of ways of preserving their lives for a few months.
He claimed they should not expect National Health Service time and money to be spent on research into prolonging life.
In fact, he went further and explained it was their social responsibility to "live dangerously".
But if he seemed to be encouraging recklessness in the older generation, in August 2000, he was able to present a study showing the success of his message about the risk of cigarettes.
The number of lung cancer sufferers in Britain has fallen, and the huge carnage wreaked by smoking has been massively reduced.
Fifty years from the date of his first breakthrough study of tobacco, Sir Richard was able to enjoy the fruits of a lifetime of groundbreaking work.
Sir Richard was married with one son and one daughter.