Previous comments on nanotechnology by the heir to the UK throne led newspapers to report that he feared that the world could be overrun by so called 'grey goo'. In his latest intervention however, published on 11 July in the UK's Independent on Sunday, Prince Charles denied that he ever held such fears.

'For the record, I have never used that expression and I do not believe that self-replicating robots, smaller than viruses, will one day multiply uncontrollably and devour our planet. Such beliefs should be left where they belong, in the realms of science fiction,' states the Prince.

In fact, Prince Charles describes the ability to work on the nano scale as 'a triumph of human ingenuity', and accepts that the technology is the subject of huge scientific interest and commercial potential.

'But how are we going to ensure that proper attention is given to the risks that may also ensue,' he asks. 'Discovering the secrets of the Universe is one thing; ensuring that those secrets are used wisely and appropriately is quite another.'

Prince Charles says that it is important, even at this early stage, to ensure that risk assessment keeps pace with commercial development, arguing that more could be done at EU level to achieve this aim.

'This is clearly a very fast-moving area of science, involving many disciplines, yet if we look at the EU's research programme for nanotechnology, only an estimated 5 per cent of total funding is being spent on examining the environmental, social and ethical dimensions of these technologies. That certainly doesn't inspire confidence,' he said.

The Prince's comments were welcomed by the UK academy of sciences, the Royal Society. Its executive secretary, Stephen Cox, said: 'The Prince's article is designed to stimulate public debate about nanotechnology, which we welcome.'

'We agree with the Prince that researchers, industrialists, policy makers, campaigners and senior public figures all share a responsibility not to exaggerate the possible impacts, either good or bad, of nanotechnology and to promote informed public debate,' Mr Cox added.

Meanwhile, a transatlantic organisation called the action group on erosion, technology and concentration (ETC Group), called on 9 July for a moratorium on the use of synthetic nanoparticles in the lab and in any commercial products until governments adopt best practices for research.

Jim Thomas, a programme officer for ETC Group, said: 'Only a handful of toxicological studies exist on engineered nanoparticles, but not-so-tiny red flags are popping up everywhere.'

The group dismisses the concept of grey goo as a 'red herring', but argues that in the emerging field of nanobiotechnology 'the spectre of 'green goo' poses an urgent need for foresight and caution.' As a result, it calls on the international community to establish a new body to track, evaluate and accept or reject new nanotechnologies, backed by an international convention on the evaluation of new technologies.

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