In an interview published on Saturday by the German magazine Focus, Professor Hawking argues that the increasing sophistication of computer technology is likely to outstrip human intelligence in the future. He concedes that the scientific modification of human genes could increase the complexity of DNA and "improve" human beings.

"In contrast with our intellect, computers double their performance every 18 months," says Hawking. "So the danger is real that they could develop intelligence and take over the world."

The best-selling author of A Brief History of Time says "we should follow this road [of genetic engineering] if we want biological systems to remain superior to electronic ones."

Hawking predicted last year that genetic engineers would be able to create super-humans with larger brains and an increased IQ. His latest warning calls for the development of technologies that would allow human brains to be linked to computers, "so that artificial brains contribute to human intelligence rather than oppose it."

The 59-year-old mathematics professor is a victim of Lou Gehrig's disease -- the nerve-destroying motor neurone illness that has confined him to a wheelchair. He also holds a Cambridge University chair once held by Sir Isaac Newton.

Professor Hawking is not alone among highly reputable scientists who foresee such a future. His comments echo those of Sun Microsystems co-founder and chief scientist Bill Joy who in March 2000 warned of the potential dangers in the computer technologies he helped create.

In a Wired magazine article, Joy cautioned that the convergence of genetic engineering and computer technology could pose a very real threat to humanity and the ecosystem.

According to Joy, current advances in molecular electronics mean that by the year 2030, "we are likely to be able to build machines in quantity a million times as powerful as the personal computers of today", and imbue them with human-level intelligence.

"With the prospect of human-level computing power in about 30 years, a new idea suggests itself," wrote Joy. "I may be working to create tools which will enable the construction of the technology that may replace our species. How do I feel about this? Very uncomfortable."

Later this month sees the UK release of Stephen Spielberg's film A.I.--a science fiction creation of Stanley Kubrick's that the late director never lived to finish. Set in the mid-21st century, the film portrays a self-aware computer that saves the world from an environmental disaster caused by the Greenhouse effect.