An international team, led by the Tel Aviv University in Israel, has developed the new machines – 100 times smaller than cancer cells – which it hopes could be used to treat the patients in just three years' time.

According to the scientists, sending drugs straight to cancer cells means they don't damage other surrounding healthy tissue, and as the materials used to create the machines occur naturally in the body, they are unlikely to be attacked by the patient's immune system.

Tests on laboratory rodents showed that the machines can work successfully and the team is now planning to conduct experiments on humans.

"We have tested this on mice and they were all fine and now we are ready to test it on people. The important thing is we only use things that the body recognises, so its immune system won't attack them, as they do with other technologies.

"We will probably start with blood cancers because the cells would be floating around and will be easier to find. But cancer is very clever and it will learn to avoid what we are doing and we will have to keep up – it is a war we are in,"

'The Daily Telegraph' quoted team leader Dan Peer as saying. The news came just weeks after a team of scientists announced that they had developed similar technology to carry out potentially life saving operations inside arteries.

In fact, the new machines, part of a growing trend for nano-technology, recall the plots of Hollywood science fiction movies, including 1987's 'Innerspace' with Dennis Quaid and 1966 film 'Fantastic Voyage', starring Raquel Welch.