At its heart, the case for animal experimentation rests on a simple utilitarian equation: animal suffering in medical research is worth less than the human benefit that results. This received wisdom appears rational and self-evident but the simplicity of the utilitarian argument is no more than the attractive face of an ugly reality.

If utilitarianism were really our guiding principle, we would experiment on ourselves. Ninety per cent of drugs that pass animal tests fail in humans and billions of dollars are wasted on animal research that leads us down blind alleys. Involving people in the dangerous, speculative early stages of medical research would yield benefits for the rest of us. But we don’t believe that sacrificing a few babies would be worth it if it helped to cure cancer – and we are absolutely right. Means don’t justify ends, so why do we think they do when it comes to animals?

This discrimination relies on difference (as the abuse of the weak by the strong always does). Animals lack our mental powers, moral capacities and a place in our community, goes the argument. But we don’t apply that principle to our own mentally, socially or morally subnormal and experiment on the sick, the isolated or the criminal. Universal human rights don’t rest on our capacities, which are not universal, but on our vulnerabilities, which are. If we can be hurt and if we value our lives, we earn the right to moral protection. Animals suffer and want to live too. If we recognise that the basis of human rights is the protection of the weak, we cannot deny the most basic of those rights to others who suffer and are powerless.

Animals aren’t means to our ends - but even if they were, the calculation is wrong. The only sure outcomes of animal experiments are dead animals. Millions of animal experiments have failed to yield cures to AIDS, strokes, Alzheimer’s and other diseases. How can we say that a speculative theoretical benefit outweighs the known cost in suffering and death? This isn’t balancing saving a dog against saving a duchess – it’s balancing a known against an unknown. And, crucially, that’s something we don’t need to do.

According to Unicef, around 10 million children under five die of preventable causes each year. Meanwhile, if you’re working class in the UK, you’re likely to die seven years earlier than a professional. Forty percent of all cancers can be prevented and many can be cured yet, to quote the World Health Organisation “more than 70% of all cancer deaths occur in . . . countries, where resources available for prevention, diagnosis and treatment . . . are limited or nonexistent.” If saving lies is our goal, we can achieve that without a single mouse being given cancer or a single monkey poisoned to death.

If cost-benefit is our guide, why not sell our iPods and use the money to buy life-saving mosquito nets? While those of us who are fortunate and privileged are unwilling to live a little less comfortably to save people ourselves, we earnestly endorse the wholesale killing of animals on the merest possibility of benefit. Talk of a moral obligation to inflict harm is cant: sacrificing others before making the merest sacrifice yourself is a long, long way from doing the right thing.

We can have medical research without animals but the issue is bigger than that. The case for inflicting justified harm – whether made by governments, scientists or terrorists – must always be treated with suspicion. Animal experimentation is an act of unconscious hypocrisy by a society whose values – including the real value we put on human life - are confused and inconsistent, and whose moral capacities are far, far more rudimentary than we like to believe.