LONDON, Oct 18 (Reuters) - London's Science Museum has cancelled a talk by a Nobel prize-winning geneticist who suggested black people were less intelligent than white people.

Dr James Watson, winner of a Nobel prize for his part in discovering the structure of DNA, had been due to speak at the museum on Friday.

Watson, an American, sparked uproar by telling Britain's Sunday Times he was "inherently gloomy about the prospects 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."

The 79-year-old geneticist said he hoped that everyone was equal but countered that "people who have to deal with black employees find this is not true."

The Science Museum, which had been due to host Watson on a visit to Britain publicising his latest book, said this was unacceptable.

"We know that eminent scientists can sometimes say things that cause controversy and the Science Museum does not shy away from debating controversial topics," it said in a statement.

"However we feel that Dr Watson has gone beyond the point of acceptable debate and we are, as a result, cancelling his talk."

Tickets for the talk had been sold out.

Watson was one of three people who shared the 1962 Nobel Prize for medicine.