One of the world's most eminent scientists was embroiled in an extraordinary row last night after he claimed that black people were less intelligent than white people and the idea that "equal powers of reason" were shared across racial groups was a delusion.

James Watson, a Nobel Prize winner for his part in the unravelling of DNA who now runs one of America's leading scientific research institutions, drew widespread condemnation for comments he made ahead of his arrival in Britain today for a speaking tour at venues including the Science Museum in London.

The 79-year-old geneticist reopened the explosive debate about race and science in a newspaper interview in which he said Western policies towards African countries were wrongly based on an assumption that black people were as clever as their white counterparts when "testing" suggested the contrary. He claimed genes responsible for creating differences in human intelligence could be found within a decade.

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The newly formed Equality and Human Rights Commission, successor to the Commission for Racial Equality, said it was studying Dr Watson's remarks "in full". Dr Watson told The Sunday Times that he was "inherently gloomy about the prospect of Africa" because "all our social policies are based on the fact that their intelligence is the same as ours – whereas all the testing says not really". He said there was a natural desire that all human beings should be equal but "people who have to deal with black employees find this not true".

His views are also reflected in a book published next week, in which he writes: "There is no firm reason to anticipate that the intellectual capacities of peoples geographically separated in their evolution should prove to have evolved identically. Our wanting to reserve equal powers of reason as some universal heritage of humanity will not be enough to make it so."

The furore echoes the controversy created in the 1990s by The Bell Curve, a book co-authored by the American political scientist Charles Murray, which suggested differences in IQ were genetic and discussed the implications of a racial divide in intelligence. The work was heavily criticised across the world, in particular by leading scientists who described it as a work of "scientific racism".

Dr Watson arrives in Britain today for a speaking tour to publicise his latest book, Avoid Boring People: Lessons from a Life in Science. Among his first engagements is a speech to an audience at the Science Museum organised by the Dana Centre, which held a discussion last night on the history of scientific racism.

Critics of Dr Watson said there should be a robust response to his views across the spheres of politics and science. Keith Vaz, the Labour chairman of the Home Affairs Select Committee, said: "It is sad to see a scientist of such achievement making such baseless, unscientific and extremely offensive comments. I am sure the scientific community will roundly reject what appear to be Dr Watson's personal prejudices.

"These comments serve as a reminder of the attitudes which can still exists at the highest professional levels."

The American scientist earned a place in the history of great scientific breakthroughs of the 20th century when he worked at the University of Cambridge in the 1950s and 1960s and formed part of the team which discovered the structure of DNA. He shared the 1962 Nobel Prize for medicine with his British colleague Francis Crick and New Zealand-born Maurice Wilkins.

But despite serving for 50 years as a director of the Cold Spring Harbor Laboratory on Long Island, considered a world leader in research into cancer and genetics, Dr Watson has frequently courted controversy with some of his views on politics, sexuality and race. The respected journal Science wrote in 1990: "To many in the scientific community, Watson has long been something of a wild man, and his colleagues tend to hold their collective breath whenever he veers from the script."

In 1997, he told a British newspaper that a woman should have the right to abort her unborn child if tests could determine it would be homosexual. He later insisted he was talking about a "hypothetical" choice which could never be applied. He has also suggested a link between skin colour and sex drive, positing the theory that black people have higher libidos, and argued in favour of genetic screening and engineering on the basis that "stupidity" could one day be cured. He has claimed that beauty could be genetically manufactured, saying: "People say it would be terrible if we made all girls pretty. I think it would great."

The Cold Spring Harbor Laboratory said yesterday that Dr Watson could not be contacted to comment on his remarks.

Steven Rose, a professor of biological sciences at the Open University and a founder member of the Society for Social Responsibility in Science, said: "This is Watson at his most scandalous. He has said similar things about women before but I have never heard him get into this racist terrain. If he knew the literature in the subject he would know he was out of his depth scientifically, quite apart from socially and politically."

Anti-racism campaigners called for Dr Watson's remarks to be looked at in the context of racial hatred laws. A spokesman for the 1990 Trust, a black human rights group, said: "It is astonishing that a man of such distinction should make comments that seem to perpetuate racism in this way. It amounts to fuelling bigotry and we would like it to be looked at for grounds of legal complaint."