Some of Britain's most senior scientists have angrily denounced suggestions that Sir Richard Doll, who proved the link between smoking and lung cancer, had deliberately failed to disclose financial dealings with the chemicals industry.

The scientists said that tens of millions of people owed their lives and health to studies pioneered by Sir Richard. "It is with dismay that we now hear allegations against him that he cannot rebut for himself," the scientists say in an open letter.

Sir Richard, who died last year aged 92, had received consultancy fees of $1,500 a day from Monsanto during the 1980s and several thousand pounds from the Chemical Manufacturers Association, Dow Chemicals and ICI. Although friends and colleagues insist that Sir Richard made no secret of his private consultancies, his close links with the chemicals industry were not widely known.

However, unlike today, there were no rules then about declaring financial interests. Colleagues of Sir Richard point out that it is only in recent years that scientists have been required to disclose financial interests. In any case, they argue, Sir Richard donated his fees to charity.

They also point out that the news of his dealings with the chemicals industry came from his own papers which he had donated to a museum of medical history.

In the open letter, the head of the Medical Research Council, Professor Colin Blakemore, and five other leading scientists strongly support Sir Richard against allegations that his science was compromised. "We feel it is our duty to defend Sir Richard's reputation and to recognise his extraordinary contribution to global health, which began in 1950 with his first [scientific] paper demonstrating a link between smoking and lung cancer," they say.

"He played a key role in the development of randomised controlled clinical trials - now the standard method by which new treatments are evaluated. He also helped identify several occupational hazards, most notably asbestos, and assess reliably the dangers of radiation," they say.

The letter is co-signed by Lord Rees, the president of the Royal Society; Mark Walport, director of the Wellcome Trust; Professor John Bell, president of the Academy of Medical Science; Professor Alex Markham, head of Cancer Research UK and Sir Richard Peto of Oxford University, who worked alongside Sir Richard for 30 years.

The authors say that Sir Richard willingly made his expert advice available to industry and to government.

"On the basis of those papers, it has recently been suggested that Sir Richard's advice to industry somehow compromised his own publications.

"We know of no evidence to support this allegation. Sir Richard was open about these consultancies and felt it appropriate that companies should seek expert advice on the safety of their products," the letter says.

Professor Peto said: "Twenty years ago people often did not disclose funding when writing scientific papers. Nowadays, it is not only standard practice, it is mandatory. I think this change is an improvement, and so did Richard Doll."

The letter

Sir Richard Doll was one of the world's greatest cancer researchers. It is with dismay we hear allegations against him he cannot rebut. His extraordinary contribution to global health began in 1950 with his first paper demonstrating a link between smoking and lung cancer. He played a key role in developing randomised controlled clinical trials, among many other invaluable contributions. It has been said his advice to industry compromised his publications. We know of no evidence for this. He was open about consultancies and felt companies should seek expert advice on the safety of products.

Professor Colin Blakemore; Dr Mark Walport; Lord Martin Rees; Professor John Bell; Professor Alex Markham