Min piglets at the experimental station at the Institute for Animal Science, in Beijing, China [photo credit: ILRI/Mann].

The pig, which looks and behaves like an ordinary pig, contains genes from mice and Ecoli bacteria that allow it to digest phosphate. This makes pig waste less damaging to the environment and also improves pig feeding.

With world population still increasing (it is expected to plateau at mid-century), some formerly anti-GM food experts are now changing their views as the balance of promised benefits (more food produced at less environmental cost) are weighed against perceived risks (the GM animals are somehow dangerous for humans).

Mr Cooke says: "When it comes to what we eat the use of genetically modified animals has drawn fierce debate. For some it is a solution to feeding a hungry planet while cutting down pollution at the same time. For others it is considered a scary case of science unhinged."