"Discovering the secrets of the universe is one thing," he said, "ensuring that those secrets are used wisely and appropriately is quite another." With this in mind, the prince says he is delighted that the Royal Society and Royal Academy of Engineering are conducting a study on nanotechnology. The results of that study, which began in June 2003, are due out imminently.

The prince also claimed in the article that he has never used the expression "grey goo". There was a media furore following comments on nanotechnology he made in April 2003. "I do not believe that self-replicating robots, smaller than viruses, will one day multiply uncontrollably and devour our planet," he said. "Such beliefs should be left where they belong, in the realms of science fiction."

Eric Drexler, the initial source of "grey goo" fears, is in apparent agreement. Last month he revealed in the journal Nanotechnology that he no longer believes self-replication is an essential part of the molecular manufacturing process.

"This makes fears of accidental runaway replication - loosely based on my 1986 grey-goo scenario - quite obsolete," Drexler told nanotechweb.org. "Chris Phoenix [of the Center for Responsible Nanotechnology] and I wrote the paper to counter the main threat posed by grey goo, which is that all the hype diverts attention from more important issues - research directions, development paths, and the role of advanced nanotechnologies in medicine, the environment, the economy and in strategic competition."

But back to Charles, who said in his article that the public will only accept nanotechnology if attitudes and regulation are encouraged to develop at the same rate as the technology itself, and if a precautionary approach is seen to be adopted.

"There will also, I believe, have to be significantly greater social awareness, humility and openness on the part of the proponents of emerging nanotechnologies than we have seen with other so-called 'technological advances' of recent years," he wrote.