If a stretch of chalk stream can be a person in law, why can't a pig?

In 2017 New Zealand's Parliament did something remarkable: it passed a law making a river a legal person. The Te Awa Tupua (Whanganui River Claims Settlement) Act 2017 declared the Whanganui River a legal person, with all the corresponding rights, powers, duties and liabilities of a legal person, exercised on its behalf by two guardians, one appointed by the Crown and one by the local Whanganui iwi.

England hasn't done anything quite like that yet, but it's been trying in a smaller and more local way. In 2025, Test Valley Borough Council voted unanimously to back a motion recognising rights for the River Test: the right to flow “unimpeded, seasonal and natural," to be free from pollution and contamination, and the right to "feed and be fed by" sustainable aquifers and other freshwater sources". Media coverage widely described this as granting the river "personhood." That's not quite right. Legal commentators have pointed out that a council motion cannot confer legal personhood on a river in the way the Whanganui Act did; it cannot give the river standing to sue anyone. Its real effect is to bind the council's own future planning and land-use decisions not to create a new legal person capable of bringing actions in court. However, this is still a significant step towards personhood — a point we will return to.

The Test wasn't even the first UK river to get this treatment. That honour belongs to the River Ouse in Sussex, where Lewes District Council approved the Rights for the River Ouse Charter in February 2025, explicitly described by the solicitors who covered it as "not legally binding," but as providing a framework for what the Charter itself calls "a renewed relationship between people" and nature, recognising the river's fundamental interests alongside our duty of care towards it. This followed a 2023 motion committing the council to draft that Charter in the first place. Since then the idea has spread fast: more than thirty rivers across the UK are now pursuing charters of their own, coordinated through a new River Rights Network. Campaigns are underway for the Frome, the Findhorn, the Cam, the Helford, and others.

None of this happened by accident, and the direction of travel is clear even if the UK hasn't reached Whanganui's destination. As the House of Commons Library notes: legal personhood is a real legal mechanism the same one that lets a company hold rights and duties, and formally granting it to a river would change who can walk into a courtroom on the river's behalf. None of the UK's rivers have quite got there yet. But the charters are clearly building towards that same idea, council by council, and a UK Parliament petition is already calling for rivers in England to be granted legal personhood.

It's a genuinely exciting development, and one worth celebrating. But it also leaves an uncomfortable question hanging in the air.

The question nobody is asking

As far as modern science tells us, a river is not an animal. A river cannot feel pain. It cannot suffer, fear, or grieve. It cannot recognise itself in a mirror or scream when it's hurt. And yet, English rivers are being recognised as entities with interests worth protecting in law. At the same time a pig in a farrowing crate, a beagle in a testing lab, and an octopus in a research tank remain, in the eyes of the law, a thing.

This isn't a criticism of the rights of nature movement. It's a question of what the logic behind it invites. If we're willing to move towards legal personhood for a river because it has ecological and cultural value worth protecting, on what basis do we withhold it from beings who can actually experience that protection?

The UK has technically already answered part of this question. The Animal Welfare (Sentience) Act 2022 recognised for the first time in domestic law that animals are sentient beings capable of experiencing "feelings such as pain or joy." Its scope covers all vertebrates, plus decapod crustaceans and cephalopod molluscs following an LSE-led review that found strong scientific evidence of sentience in those species.

Whilst we champion any progress for animals, in practice, this Act is a modest one. The Act doesn't grant animals broad rights. It creates an Animal Sentience Committee that can check whether government policy has paid "due regard" to how it might affect animal welfare. As legal commentary on the Act has pointed out, this is a thin right: the government must consider animal welfare but nothing in the Act compels the government to actually prioritise it. Meanwhile the definitions of "animal" remain inconsistent across UK law, and the Animal Sentience Committee itself has flagged substantial gaps in enforcement. The government has declared, in statute, that animals can feel joy and pain. Yet it decided that this doesn’t matter very much when it conflicts with convenience, tradition, or profit.

Thin rights versus thick rights

There's a useful distinction in animal rights theory between "thin" and "thick" rights. Thin rights require that an animal's interests be considered: the Sentience Act model. Thick rights protect an animal's fundamental interests outright, such as a right not to be made to suffer unnecessarily for food or clothing. Almost everything the UK has done for animals so far, such as the Animal Welfare Act 2006, the Sentience Act, and welfare codes for farming and transport, sits in the "thin" category. It regulates how animals may be used. It does not ask whether they should be treated as usable property in the first place.

Legal personhood is what could move an animal from the thin category to the thick one. Dr Joe Wills, a legal academic at the University of Leicester and a member of the UK Centre for Animal Law's Working Group on Animal Personhood, has spent much of his career making this case in the UK specifically. As he explains it, being a "person" in law is not some special metaphysical status reserved for humans: it merely means that an individual or entity is entitled to have certain interests enforced in court, which we already recognise for a range of nonhuman entities such as corporations, states and natural entities. Personhood, in other words, is exactly the legal device that Whanganui already has, and the one the UK's river charters are visibly reaching towards, even if they haven't got there yet.

The gap between thin and thick rights has deep roots that predate every welfare statute the UK has ever passed. Wills traces it back to the 18th-century jurist Sir William Blackstone, who treated the biblical grant of "dominion" over animals as the "only true and solid foundation" of man's dominion over external things, meaning animals were, in law, resources to be owned, exploited and traded like any other commodity. Over a century later, that view was still largely prevalent: a popular English jurisprudence textbook published as late as 1966 stated flatly that "the law is made for men, and allows no fellowship or bonds between them and the lower animals." This view subsisted despite over a century of animal protection statutes having been passed by that point. Thin rights have been layered on top of animals' property status since the 19th century but none of them have touched the Blackstonian foundation underneath. Passing another welfare law doesn't ask the thick-rights question.

English law has done this before, just not for animals

Personhood for a non-human entity does not require reinventing English law from scratch. English law already grants legal personhood to something else entirely: the company. As recognised in the House of Lords' landmark 1897 ruling in Salomon v A Salomon & Co Ltd, a properly incorporated company has been treated as "a different person altogether" from the people who own or run it. The company is a legal person capable of owning property, entering contracts, and suing or being sued in its own right entirely independent of its shareholders. Nobody thinks a company can suffer or feel joy yet English law made it a person anyway.

Wills points out that English courts have ruled other inanimate objects as persons. The Judicial Committee of the Privy Council affirmed the separate legal personality of a Hindu idol as early as 1925, and in 1991 the Court of Appeal recognised the legal personality of ruined temples in a foreign jurisdiction as a matter of English law. More recently, Lord Hodge, Deputy President of the UK Supreme Court, has floated the idea of a separate legal personality for artificial intelligence. Companies, idols, ruined buildings, and potentially software have all been treated as candidates for personhood in English legal reasoning. Yet sentient animals have not.

Comparing the UK to the United States, where the Nonhuman Rights Project has spent over a decade litigating for great apes, elephants, and other animals, Wills points to a UK legal culture that has historically pursued animal protection through lobbying Parliament rather than through the courts. This is partly due to a stronger doctrine of Parliamentary sovereignty that makes English judges more deferential to the legislature than their American counterparts. In addition, the fact that animal law is taught and researched far less in the UK than in the US, producing a thinner intellectual pipeline for novel litigation strategies of the kind that have at least got a hearing in American courts. There isn't anything in English law that forecloses this. It's just that nobody in the UK has built the case in front of a judge.

What happened when someone actually tried (in New York, not London)

One of the most sustained attempts to litigate animal personhood in a common law court is the case of Happy, an Asian elephant held alone at the Bronx Zoo for decades. The Nonhuman Rights Project ("NhRP") brought a habeas corpus petition on her behalf (habeas corpus being the ancient writ used to challenge unlawful detention). NhRP argued that Happy as a cognitively complex and autonomous being should be recognised as a legal person with the right to bodily liberty and transferred to a sanctuary. Underpinning the argument was the fact that in 2005 Happy became the first elephant to "pass" the mirror self-recognition test, which is considered an indicator of self-awareness.

The case got remarkably far, and it drew in UK legal scholarship along the way: Wills himself helped draft and coordinate an amicus brief signed by 36 UK-based legal academics, barristers and solicitors with expertise in animal law, and they filed in support of recognising Happy as a legal person. In 2021, New York's Court of Appeals agreed to hear the case: the first time the highest court of any English-speaking jurisdiction had agreed to hear a habeas corpus claim brought on behalf of a non-human.

No English court has been asked to rule on animal personhood in anything like this way, and no equivalent litigation campaign has been mounted on British soil. It's an American case, decided under American common law, brought by an American organisation. Yet the intellectual groundwork has been laid, UK legal academics have already put their names to it, and English courts have a track record of recognising personhood in far stranger non-human entities. What's missing isn't legal capacity. What's missing is a case.

In 2022, New York's court ruled against Happy, 5–2. Chief Judge Janet DiFiore held that "the writ of habeas corpus" is intended to protect the liberty right of human beings to be free of unlawful confinement, and that it therefore has no applicability to Happy, a nonhuman animal who is not a 'person' subjected to illegal detention. But the dissents are where the argument's future lives. Judge Rowan Wilson's dissent traced the writ's own history to make the point directly: "Most fundamentally, the writ was" used to grant freedom to slaves, who were considered chattel with no legal rights or existence. Judge Rivera went further, concluding her dissent with the words: "an affront to a civilized society, and every day she remains a captive — a spectacle for humans — we, too, are diminished.”

Happy never got her sanctuary. She died at the Bronx Zoo on 26 May 2026, still confined, after nearly fifty years in captivity.

"But animals can't hold duties" and other objections

A standard objection to animal personhood is that legal persons must be capable of bearing legal duties as well as rights and animals plainly can't. It has a serious problem: the same is true of human infants and comatose adults, yet few people suggest they should therefore be denied rights or the ability to have someone seek relief on their behalf. Rights and duties have never been perfectly bundled together in law for humans or otherwise.

The second objection is the slippery slope: if an elephant is a person what about a chicken? An ant? Where does it stop? This objection misunderstands how courts actually work. Common law systems don't operate by pure logical extension from first principles: they are, by design, conservative institutions. Scholarship on judicial behaviour has long found that courts are constrained from producing genuine social change on their own and tend to contribute to it only where there is already broad political and cultural support for that change. This dynamic is explored in Gerald Rosenberg's The Hollow Hope: Can Courts Bring About Social Change?, which found that even the U.S. Supreme Court's most celebrated rulings rarely moved society forward on their own but tended to ratify shifts in opinion that had already happened. A review of this literature specifically applied to animal advocacy concludes something similar: public opinion and judicial opinion move together over time, meaning strategic litigation is far more likely to succeed once cultural attitudes have already begun to shift rather than forcing that shift into being from the bench.

That's why the slippery slope doesn't hold. If our culture isn't yet willing to treat an ant as a being with morally relevant interests there's very little prospect of a court leaping ahead of that consensus to declare them a legal person. English judges, as Wills notes, are especially reluctant to get ahead of Parliament. A judge in New York put the underlying pattern well: even in rejecting an early NhRP case, Justice Barbara Jaffe observed that courts "are slow to embrace" change and occasionally seem reluctant to engage in broader and more inclusive interpretations of the law. Personhood for elephants or great apes is a live question precisely because cultural attitudes towards those animals, such as their intelligence, their capacity to suffer, their similarity to us, have already shifted substantially. Nobody is making the equivalent cultural argument for ants. The slope is a great deal less slippery than it looks because the courts that would have to slide down it are conservative by nature and will only move as far and as fast as the culture around them allows.

On the sameness-with-humans point more broadly Wills is honest that it cuts both ways. Asked whether grounding animal rights claims in similarity to humans just reinforces the idea that humanness is the yardstick for moral worth, he agreed that ethically, animal worth shouldn't be measured by closeness to humans at all but noted that legally, since judges build new precedent by analogy to old precedent, demonstrating that animals are relevantly like humans is "obviously extremely important" to actually winning a case in a common law court. It's a pragmatic compromise, not a philosophical ideal, but it's also the kind of incrementalism that got the River Ouse its charter.

It's worth stressing that nobody is arguing for animal personhood to mean identical rights to humans or for it to apply to every animal at once. Wills is candid that personhood strategies realistically stand a chance, for now, only for a narrow, privileged group of species, such as those sharing certain cognitive capacities with humans or those from endangered species, and that it's "unimaginable" that a court could order the release of the tens of billions of animals currently in farms and laboratories on this basis. That's a limitation, not a flaw in the underlying case, and it's a limitation the river movement shares. The River Test and River Ouse didn't wait for a national theory of nature's rights covering every stream in Britain: they built momentum one charter, one council, at a time.

What personhood would actually mean for a UK animal

Legal personhood for an animal in England wouldn't mean animals could vote, own property, or be prosecuted for crimes (any more than the Test can be prosecuted for flooding a village). Drawing on how the concept already operates elsewhere in English law and in comparable common law jurisdictions, it could mean:

1. Standing to sue. A guardian or advocate, the same structure Whanganui already has and the one UK river campaigners are ultimately lobbying for could bring legal action on an animal's behalf against those who harm them, rather than relying on the state to prosecute under welfare law.

2. A shift from "thin" to "thick" protection. Instead of merely requiring that an animal's interests be considered, certain fundamental interests, such as freedom from confinement that thwarts basic natural behaviour or freedom from being killed for non-essential human purposes, could become legally binding and not just factors to weigh against convenience.

3. A change to property status. As Wills notes in relation to the Argentine case of Cecilia, a chimpanzee whose personhood claim succeeded in 2016, one clear legal option is to declare that an animal cannot be owned as property at all because persons cannot be owned. There is English precedent for this argument in Somerset v Stewart (1772), in which Lord Mansfield held that "the state of slavery... is so odious, that nothing can be suffered to support it, but positive law," and ordered Somerset discharged because no such law existed in England. Alternatively, a court could preserve an owner's property interest while still finding that the animal's interest in liberty outweighs it in a given case.

England already has a template for this sitting right there in its rivers: local recognition, campaigner-drafted charters, and pressure building council by council until Parliament has to take notice. What's been missing on the animal side isn't a legal gap. What's missing is a case, a campaign, and willingness to try.

The question the rivers movement leaves us with

It's genuinely good news that local councils have recognised the River Ouse and the River Test as holders of “rights”. It's good for the water, good for the wildlife who depend on it, and good precedent for anyone who thinks the law should protect things or individuals who can't protect themselves in court.

If English law is now sophisticated enough to move towards recognising a body of water, companies, idols, and ruined temples, as entities with legal rights, it is difficult to fathom that it's too radical an idea to give the same consideration to a being capable of experiencing the outcome. The rivers movement didn't wait for a national consensus or an Act of Parliament: it built momentum charter by charter, council by council, until the idea became unremarkable. Animal law in the UK has the same option available. As Dr Wills's own work suggests, the only real question is whether British lawyers are willing to take it.

Lawyers for Animals, a registered charitable incorporated organisation in England & Wales. Principal Office: Studio 10 Hackney Downs Studios, 17 Amhurst Terrace, Lower Clapton, London E8 2BT. Registered Charity No: 1215659.