"allergic to cats" - is there such a thing as a cat allergy which has serious allergic consequences? In my view, a neighbour with a cat allergy would simply have to avoid touching cats - they would not be entitled to govern their neighbours' possession of cats. And as for goldfish, it's incumbent on the goldfish owner to secure them - there is no obligation on the cat owner to monitor the cat's appetites and intentions!

I agree that nuisance may apply in extreme cases - such as where the overall number of cats kept is completely abnormal. But I do not believe nuisance could ever apply to a single cat whose behaviour is only typical of cats.

Ok, so where does the "free spirit" "right to roam" advice come from then? That belief seems extremely widespread, yet this answer seems to be saying there's a somewhat significant chance that you could, as a cat owner, be found liable if your cat so much as attacks a neighbour's cat (I can't imagine how many people up and down the country could be found liable under this!)

I don't think "free spirit" is an actual term of law, for all that it seems to crop up online. My understanding as expressed above is that you can be liable for your cat's actions, but if it's a normal cat doing normal cat stuff, and you're not negligent in the way you look after it, then you wouldn't be. As ever, the word "reasonable" is doing a lot of work.

@Steve cat allergy has similar symptoms to the rabbit allergy that runs in the other side of my family - luckily mildly because the mild symptoms are shortness of breath when within a few metres downwind or sharing an enclosed space. No contact required. A more severe case combined with a cat that likes to enter other houses could get quite serious (or a very friendly cat sneaking up on a sunbathing allergic neighbour and rubbing against their face, etc.)

Cats were explicitly discussed when the bill was being debated: hansard.parliament.uk/Lords/1970-10-29/debates/…. The law was deliberately drafted such that cats would not be included.

@JoeStevens This is the distinction in Section 2 mentioned above. A normal cat behaving normally will not entail strict liability, but if a cat (or any animal) is unusually dangerous, either all or some of the time, and the keeper knows about it, then the liability could be engaged. Cats are not immune unconditionally - the cited paragraph is about "quite normal acts on the part of such an animal" (e.g. a cat), which are not covered, but abnormal acts might be.

@Steve I am allergic to cats myself and I agree with ChrisH. Physical contact isn't needed, but you need to get close to (and downwind from) a cat outdoors or enter a room that is frequented by cats. It mostly the hair and skin-particles that trigger the allergy. Some breeds of cats (short haired, little hair-shedding) are less problematic regarding allergies. E.g. the Devon Rex is usually not causing (major) issues. Friend of mine has one and I can spend several hours in its company (even pet it) with only a hardly noticeable light reaction. (I still wash my clothes afterwards to be safe.)

Can't help feeling that a full answer to all the issues raised here could easily be an undergraduate project, or even a multi-volume law textbook.

@JoeStevens Care to point to the precise areas in there where cats were discussed?

From a purely practical standpoint, it's a LOT easier to keep cows on your property than cats. A simple low fence or a shallow ditch will stop most cows trying to cross it, but you'd have to build pretty high walls to contain a sufficiently determined cat, or else keep them indoors all the time.

@Tonny I've seen the Rexes and Sphinx cats described as hypoallergenic. It's probably something to do with the genetic mutations that give them a very different coat (or none for the Sphinx) - plus less fur means less shedding

@ChrisH No cat is really 100% hypo-allergenic, but Rexes and Sphinxes do get called that. I react to both but the reaction is so mild (if the exposure is limited) compared to my reaction to other cats that I can more or less ignore it. People with a heavy allergic response can still have a bad reaction to them. It varies greatly from person to person.

@Tonny exactly (hence "seen..described as") - though in the sense of "below typical", "hypo-" could be right. Anyway the allergic effect of a typical cat on a typical sufferer can be serious, even dangerous if it likes to take naps on unfamiliar pillows.

@Steve Goldfish does seem like a weird example, since goldfish bowls are usually indoors and the roaming cat is outdoors. Maybe a better example would be fish in a coy pond. It would be difficult to secure this against a determined cat, although the cat would have to overcome its normal avoidance of water.

@Barmar for what it's worth, and this is now extremely off topic, I was thinking of the (outdoor) ryunkin in Connie Willis's To Say Nothing of the Dog, although in that case the cat lived in the same household

@Jez, I think others covered the point, but "free spirit" and "right to roam" are just everyday idioms, not actual legal terms. The essential legal points are that cats themselves are a kind of chattel covered by property rights, so they cannot be seized or slain like wild animals. However, the inherent characteristics of the cat species are such that they are not regulated as a dangerous animal, and their natural agility makes them difficult to contain, so they are expected and allowed to roam in the locality. (1/2)

Historically, cats helped to control vermin. Landowners in the same locality as where a cat is kept, have no right for their open land to be be free of attempted visitation from cats. They can however hassle the cat to shoo it and deter its future presence. A similar regime applies to children, really. There are unfortunately some things in life that require landowners to pay attention to their property and expend labour on maintaining their boundaries, as part of a proper balance between neighbours and between people and animals. (2/2)

@Barmar I know several people with outdoor goldfish ponds. They grow quite large when not constrained by their tank size.

"cats are not cows" [Citation required]