The world's first GM monkey, Andi, could place scientists on the threshold of new treatments for diseases such as breast cancer, diabetes, HIV, Parkinson's and Alzheimer's.

For now however, anti-vivisectionists and "primate-rights" campaigners condemn the breakthrough, fearing that it will herald an increase in experiments on monkeys.

The US scientist, professor Gerald Schatten, who led the research team, said: "We are at an extraordinary moment in the history of humans." He has been condemned by anti-vivisectionists as "abhorrent" for "playing god".

Wendy Higgins, campaigns director of the British Union for the Abolition of Vivisection said: "It is shocking that this should happen at a time when there are worldwide calls to reduce or even abolish research using primates."