Rarely can a change of two words in a political agreement have had such an effect. In the European Union's Treaty of Amsterdam, which came into force in 1999, animals were designated "sentient beings" instead of mere agricultural products. Member states are now required to pay "full regard to the welfare requirements of animals". No big shakes, you might think. But given the history of western thought, that idea is nothing short of astonishing. Animals have long been regarded as little more than lumps of meat. Aristotle said that animals, like slaves, existed for our use. Aquinas regarded them as mere instruments to whom moral considerations did not apply. Descartes thought they were automata. "There is no prejudice to which we are more accustomed," he declared, "than the belief that dumb animals think."
The first bill to outlaw bull-baiting was presented to the Commons in 1800, but the outrage was so great it took ten further attempts before it was finally enacted in 1835. It proved to be a landmark ruling. Most lefties, it must be said, joined the humanitarian protest against the animals-as-mere-brutes theory. Besant, Shaw, Hardie, Edward Carpenter and Henry Salt all urged "humanitarian politics", but to little avail. Salt (a master at Eton and a personal friend of Gandhi) founded the Humanitarian League in 1894, which campaigned as much against child cruelty and corporal punishment as it did against vivisection and the Eton beagles. In 1977, Lord Houghton (former chair of the Parliamentary Labour Party) launched a campaign to "put animals into politics", only to be greeted with derision from the Guardian, which exclaimed that we already had enough "snakes in the grass", "cunning foxes" and "sly old dogs" in the Commons.
But now, it seems, animals' time has finally come. Popular interest in animal rights is at a record level. Politicians are having to give a nod to the animal vote. Despite the personal ambivalence of Blair (and the government's huge indebtedness to business, especially pharmaceuticals and multinationals), many excesses have been curbed. Hunting with dogs has been outlawed. Experiments on the great apes are no more. Testing for cosmetics has been eclipsed. Sow stalls and veal crates are illegal, or shortly to become so. Hen batteries are being phased out. The government is currently piloting the Animal Welfare Bill, which, while full of compromises, makes the "duty of care" enforceable for the first time in law.
Scientific evidence is also now unambiguously on the side of animals. As this lively book shows, only the myopic refuse the case for animal sentiency. There is ample evidence in peer-reviewed scientific journals that all mammals, at least, experience not just physical pain but mental suffering, including fear, terror, anxiety, anticipation, stress, trauma - and to a similar degree as we do ourselves. As Konrad Lorenz noted as early as 1966: "The similarity [between humans and animals] is not only functional but historical, and it would be an actual fallacy not to humanise."
Suddenly, everyone wants to show their credentials. Keith Kenny of McDonald's assures us of the company's commitment to "progressing global standards in animal welfare". Oliver Ryan of the International Finance Corporation (the World Bank's private-sector arm) insists that, despite its support for intensive farming, it really is "engaging" its "clients" about welfare standards. Academics, too, want to be on the side of the angels. Animal welfare is an indispensable part of sustainable development, says Kate Rawles, noting that we must not be "sheepish [sic] about being compassionate". Apparently, even countries with human-rights issues are not without hope. According to the RSPCA's Paul Littlefair, China "is waking up to animal welfare".
Much more will be needed to translate even moderate concerns into practice for the billions of farm animals that modern breeding technologies have reduced to mere meat machines. Still, at least their suffering is on the agenda. And this book is an impressive marker on the road to justice for fellow sentients.
Andrew Linzey is a theologian at Oxford University and co-editor of "Animal Rights: a historical anthology" (Columbia University Press)