This week, scientists revealed they have genetically modified a pig to be resistant to disease using a "gene-editing" technique.

Some of the reports have suggested that 'Pig 26' could "win over" opponents to GM.

It certainly has not won us over, for reasons fundamental to animal welfare and the world hunger crisis.

Peter Stevenson, Compassion's Chief Policy Advisor, says: "It is ethically unacceptable to genetically engineer animals to make them more amenable for human use.

"What is more, some biotech scientists argue that GM technology in animal husbandry is key to feeding the growing world population. This is not true. We do not need GM animals to feed the growing world population. Indeed GM animals could well undermine attempts to feed the population of nine billion that is anticipated by 2050.

"GM animals are likely to be farmed industrially and fed on human-edible cereals. Such grain-based industrial livestock production is a wasteful use of cereals and damaging to the environment as it degrades water, soil and air and erodes biodiversity and ecosystems."

'Pig 26' was 'created' by researchers at the Roslin Institute in Edinburgh, where Dolly the sheep was cloned in 1996. The Roslin researchers claim that techniques similar to that used to create the new GM pig could be used to make other livestock such as cattle and sheep immune to a host of diseases.

Compassion fears that in many cases the diseases that will be addressed are those that are inherent in factory farming e.g. the diseases that are inevitable when a large number of animals are housed together in close confinement. Transgenic disease resistance should not be used as a way of facilitating the use of systems that fundamentally compromise the welfare of the animals involved. The proper way to address such diseases is to keep animals in less intensive systems in which they will be less susceptible to infection.

The intensification of livestock production, which could be encouraged by these genetically modified animals, would allow them to be kept at ever more concentrated densities and fed on human-edible grain.

Peter adds: "Far from solving the problem of world hunger, this may well intensify it by perpetuating the competition between humans and livestock for food. The only thing sustainable about that is the fact it risks sustaining the world's hunger crisis."

Research shows that feeding cereals to animals is a resource-inefficient way of producing food, as much of the food value of cereals is lost during conversion from plant to animal matter. A report by the UN Environment Programme concludes that a kilo of cereals provides six times as many calories if eaten directly by people than if it is fed to livestock. This indicates that only 17% of the calories fed to animals in the form of human-edible crops is returned for human consumption as meat or dairy products.

Animals should be fed in ways that avoid the excessive use of feed crops. Instead more emphasis should be put on:

Raising animals on extensive pastures: The great strength of extensively reared cattle and sheep is that they convert grass into food that we can eat and are able to use land that is generally not suitable for other forms of food production.

Integrated crop/livestock production: The World Bank is extremely positive about the benefits of such mixed farming as crop residues and locally grown crops can be used to feed animals. Moreover, their manure, rather than being a pollutant, fertilises the land and improves soil quality.

Reducing food waste: The European Commission's Roadmap to a resource-efficient Europe points out that in the EU we waste 90 million tonnes of food every year or 180 kg per person. Reducing food waste would enable many more people to be fed. The waste that cannot be avoided should, subject to stringent safeguards, be fed to pigs and poultry replacing much of the current cereal- and soy-based feed.

GM pigs will not feed the world