The Nobel Prize-winning scientist, who with Francis Crick and Rosalind Franklin discovered the double-helix structure of DNA, has been embroiled in controversy for more than a decade.

In 2007 he lost his job at Cold Spring Harbour Laboratory for making racist remarks, but retained three honorary titles there including chancellor emeritus.

However, following a new documentary in which he said these views had not changed, and told interviewers genes were responsible for a difference in average IQ between black and white people, they decided to take further action.

Describing the remarks as "reprehensible" and "unsupported by science", the lab said they effectively undermined an apology issued by the scientist following the original controversy.

According to top geneticists, even the most sophisticated DNA assessments are unable to find solid evidence of racial differences in intelligence.

Dr Watson told an interviewer in 2007 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 – where all the testing says not really".

He also said that while he would like everyone to be equal, "people who have to deal with black employees find this is not true".

The new comments were made in a documentary in the American Masters series on PBS, in which the creators said from the outset they would seek to address the controversy.

Now 90 years old, Dr Watson is currently residing in a nursing home after a car crash in October that has left him with "very minimal" awareness of his surroundings.

The geneticist’s son Rufus told AP that while his statements make him seem like a "bigot", that was not the case.

"They just represent his rather narrow interpretation of genetic destiny," he said. "My dad had made the lab his life, and yet now the lab considers him a liability."

Dr Watson had been involved with Cold Spring Harbour since the 1960s, serving as its director, president and chancellor.

He originally rose to fame after he and Crick revealed the double-helix model of DNA, based in part on an X-ray diffraction image captured by Franklin.

The momentous discovery made the two men world famous, and both went on to have successful careers in science.

However, Dr Watson has been dogged with accusations of racism, sexism and homophobia.

While his controversial opinions – including those concerning a link between dark skin and libido and selective abortion based on a hypothetical "gay gene" – have often been in the context of genetics, many experts have denounced them as highly unscientific.