nuisance

Falcons: turning and turning in the widening gyre – nuisance and sensitivity

1 September 2026 by David Hart KC

Thomas v. Nicholas [2026] EWCA Civ 947

This unusual neighbour dispute may clarify in time the law of nuisance upon which the Court of Appeal was divided. The CA took the unusual step of granting permission to appeal to the Supreme Court on a 2-1 decision.

The Nicholas brothers, who breed falcons for the Middle East market (£100,000 or more per bird), have an aviary near St Just in Cornwall. Next door lives Mr Thomas, whose activities on his land gave rise to this litigation. Falcons are highly sensitive to disturbance during their breeding season. Mr Thomas and his company carried out building works, operated a scaffolding storage business, and kept an excavator close to their boundary. The consequence of these activities, as HHJ Russen K.C. found at first instance, was the death of three gyr falcons, damage to falcon eggs, and total losses of £258,500. This was the culmination of a whole series of neighbour spats about septic tanks, drains and rights of way.

The judge found that these falcon-related losses were caused by private nuisance and negligence arising of the use of Mr Thomas’s land for which he and his company were responsible.

The legal controversy arises out of the principle that a claimant cannot increase the tortious liabilities of his neighbour by complaining that an over-sensitive activity on his land has been affected by the neighbour’s activities. He can only complain if he can say that his neighbour’s activity would have affected his land even if it had not been over-sensitive. The textbook case is Robinson v. Kilvert (1889) 41 Ch D88; very delicate papermaking by C affected by heat from D’s premises, which would not have affected “ordinary” papermaking.

The Nicholases sought to finesse this rule by saying that their land was a suitable place for an aviary; it was not a hypersensitive activity per se, but only during the breeding season, and given that Mr Thomas was fully aware of that short-term sensitivity, he should be found liable.

Unusually, all three Court of Appeal judges answered things differently. Whipple LJ said Mr Thomas was liable in nuisance and in negligence. Nugee LJ said he was not liable in nuisance, but liable in negligence. Moylan LJ said he was liable in neither. So, the falcon breeders won. For the moment.

Nuisance

As for nuisance, Nugee and Moylan LJJ agreed that the claimant’s falcon business was not a “common and ordinary” use of the claimants’ land. Whether an interference is “substantial” with that use and whether that use of land by the claimants is “ordinary” must both be assessed objectively — by the impact on the ordinary or average occupier, not by the particular sensitivities of the actual claimant.

As noted above, a claimant carrying on sensitive operations can still recover in nuisance, but only if the interference would substantially affect the use of his land, were it to be used for ordinary purposes. Equally, if a defendant’s use of his land is ordinary, then his neighbour cannot complain about it.

“Ordinary” is a term of art in nuisance law, on both sides of the coin, both in terms of a claimant’s use of his land and a defendant’s use of his land. The terminology dates back to Bamford v. Turnley (1862) 3 B&S 66. Some surprising activities are ordinary; to demolish your property and build another one, with all the attendant dust, noise and disturbance, may well be “ordinary,” however grim for your neighbour temporarily, as long as the builders do it competently and with proper consideration for your neighbour (or, using another 19^th term of art used in the Bamford case, “conveniently”).

One issue which weighed heavily with the judge (and Whipple LJ in the CA) was the finding that the locality was suitable for such a sensitive use as an aviary. But the suitability of a location for a particular activity, as the judge had found, does not of itself make that activity an ordinary use.

Nugee LJ gave his interpretation of the judge’s findings at [113]: the location was suitable, and therefore was not a special or unusual use, but an ordinary one. Nugee LJ thought that the therefore was a non-sequitur. The true test was whether the defendant’s actions interfered with the ordinary use of the land. The caselaw (Robertson about delicate paper, a Capetonian case about sensitive telegraphy, and their restatement in Fearn v. Tate [2023] UKSC 4) were dispositive against liability in nuisance: [126]. This analysis was endorsed by Moylan LJ at [168]ff.

By contrast, Whipple LJ concluded at [61] that it is possible to have a common and ordinary use of the land which has sensitive aspects. Nugee LJJ disagreed at [134]  “…I simply do not think it follows that because this particular part of Cornwall is a suitable location for breeding falcons, that makes it a common or ordinary use for the purposes of the law of nuisance. The warehouse used in Robinson v Kilvert was as I have said no doubt a suitable location to store things, and the Central Jetty in the Cape Town case was no doubt a suitable location to bring a cable ashore, but in neither case did this make the use of that location a common and ordinary use for these purposes; in each case the trade or business, however commonplace in other respects, had a particular sensitivity (to heat, to electric current) over and above ordinary trades, which meant that for the purposes of the law of nuisance, it was to be regarded as special.”

Nugee LJ also identifies the strongest reason for rejecting this application of this test, namely the evidence about the excavator, and its effect. It had broken down, and it had been parked near the boundary by Mr Thomas and left there. It was left with its bucket raised. It was purely this visual interference with the sight lines of the falcons which led them to “going mental”: [39]. As Nugee LJ put it at [138], this could not have crossed the threshold of constituting a substantial interference with the ordinary use of the claimant’s land. It only had an impact because of the very particular use, and was therefore not a nuisance. Most of us might have been irritated by this wayward parking of a large vehicle close to our boundary, particularly if we were irritated by our neighbour anyway, but this was not this claim. It was that it had a specific effect on the falcons and their sight lines.

Negligence

But the CA (Whipple and Nugee LJ, with Moylan LJJ dissenting) found for the Nicholases in negligence.

Mr Thomas argued that if his actions were not a nuisance, he could not be negligent, and that imposing a duty of care would prevent lawful use of his land. The law in this area, being the law of property, should be driven by nuisance principles, and to do anything else would bring incoherence into the law. The majority rejected both arguments, observing that just because Mr Thomas was not liable in nuisance, he could not act with disregard for the interests of his neighbours and cause as much disturbance to the falconry business as suited him to do so, he would not be acting “conveniently”.

The Court added that the relationship between the law of nuisance and negligence in the present circumstances was not incoherent. It held that an occupier may not be liable in nuisance (because he was carrying out an ordinary activity) yet still owe a duty of care to avoid causing specific, foreseeable harm to a particular neighbour. Mr Thomas knew the falcons were sensitive during the breeding season, and there were alternative locations where the bulldozer with its raised bucket could have been parked. The judge had also found that the use of the land for the scaffolding business was not ordinary. And the building works, though “ordinary” in themselves, were carried out without proper consideration of the falcons’ breeding season.

Moylan LJ’s dissent fastened on the fact that the same activities which were not found to be a nuisance were found to be negligent. He found that no duty of care arose in such circumstances because of the dangers of incoherence between the two torts. He considered “that the issue should be phrased as being whether a duty of care in negligence can be imposed on the owner of land the effect of which is inconsistent with the core principles of the law of private nuisance.” He concluded that it was no duty, not least because the same factual allegations gave rise a finding of no liability in nuisance but liability in negligence.

Comment

At first sight, this appears to be a rather simple case. Mr Thomas behaves in a rather unneighbourly fashion, knows his land immediately abuts the aviary and he causes losses to its owners. Most people may think he should lose. But the more you think about the legal problem, the more it causes some strain to the causes of action in nuisance and negligence, as currently formulated. Nuisance has to have some control mechanism preventing a sensitive use by C from sterilising neighbouring land uses, just as it requires the interference to C’s use of his land to be substantial. But negligence must play some part, however residual. Getting too purist risks offending against Lord Atkin’s 1941 warning about old causes of action:

“When these ghosts of the past stand in the path of justice, clanking their mediaeval chains, the proper course for the Judge is to pass through them undeterred.”

Whatever the Supreme Court says about nuisance and sensitivity, there must be room for some liability in negligence to cope with hard cases, arguably this one.

Leaky sandboxes and bursting reservoirs

28 August 2026 by David Hart KC

Strange are the ways in which AI can escape and do harm; equally strange are the curious mechanisms whereby water can escape and do harm.

Water

Let’s start in the 19^th century with water, and one of the most famous cases of all time, Rylands v. Fletcher. Fletcher owned a mine, Rylands (of The John Rylands Library fame) a local cotton mill for which he needed water from a reservoir (for steam).  The reservoir was excavated, and during the excavation five blocked vertical mineshafts were found in the bed of the reservoir. But two things were not known, namely that these vertical shafts had not been filled in very well, and also that they joined with lateral shafts leading to Fletcher’s mine (of which they had originally formed a part). After two separate escapes of water into the colliery in 1860 and 1861, the inspector of mines thought enough was enough, warned off Fletcher, who closed his mine down.

Fletcher sued Rylands, and won in the House of Lords, seven years after issue of his claim and a tortuous process through the courts. Liability was ultimately declared to be strict; Rylands did not have to know or be aware of the interconnections between his reservoir and Fletcher’s mine. For historical, technical and legal detail, see Professor A.W.B. Simpson in his superb article in the Journal of Legal Studies (vol.xiii, 1984, p.209). In short, there had been in recent memory two catastrophic reservoir bursts (78 dead in 1853, and 238 dead in the 1864 Dale Dyke breach shown in the contemporary image above), both involving municipal water supplies. The judicial atmosphere would have been such that it would be like deciding a new point of tort law about industrial explosions in the immediate aftermath of the Buncefield catastrophe in 2005. And yet the Rylands reservoir was a modest private enterprise, of such a volume that it would not even be regulated these days under reservoirs legislation. It exists, and Professor Simpson tells us that it was still leaking when he saw it.

As later cases such as Cambridge Water v. Eastern Counties Leather have clarified, liability is not that strict. Foreseeability of the relevant type of harm is necessary, but not of the mechanism by which it occurred.  Lord Blackburn put it thus

 “We think that the true rule of law is, that the person who for his own purposes brings on his land and collects and keeps there anything likely to do mischief if it escapes, must keep it at his peril, and, if he does not do so, is prima facie answerable for all the damage which is the natural consequence of its escape” (1866) L.R. 1 Ex.265, 279, Court of Exchequer Chamber.

In recent times, Rylands has become sidelined into a sub-category of private nuisance applicable to isolated escapes from land, rather than a broad authority for strict liability in tort. But it had its moment, albeit being out of synch with similar tort cases before and after it.

Escaping AI

Now to escapes of AI, and what happens when something wriggles out of its sandbox. Sandboxes are meant to keep developmental AI in. So, spool on 160 years. On 16 July 2026, an AI platform called Hugging Face told US law enforcement that an attacker had used an AI agent to breach its systems. But no human had been involved. Two OpenAI models (one released, one under development) had got out of their development sandbox and hacked Hugging Face.

More precisely, a sandbox for AI is an isolated computer environment with no internet access, except for an internal system designed to send in enough software to do no more that test the models. Its purpose is to insulate the AI models from the rest of the world. But these mischievous OpenAI models (i) exploited an unknown vulnerability in the intro/exit software, (ii) reasoned via the internet, to which they now had access, that the solutions for the problems they had been set was to be found at Hugging Face, and (iii) duly hacked it to get its answers, sending in a dataset which enabled the models to harvest login details and access internal servers.  See, for the short version, Outside the Box , The Economist, July 25, 2026, p.73, for a longer an independent report by METR (of 26 August 2026) commissioned by OpenAI. The METR report contains a helpful graphic, suggesting that at its height the attack on Hugging Face involved 1200 AI agents working together via a shared message board which the agents had created.

This is just one of a series of recent episodes involving rogue agents which has been causing embarrassment to OpenAI and Anthropic, in particular.

Where would liabilities lie for these kinds of events? This question raises a whole host of problems, much chewed over the last few years. Is the AI agent (by it or its team) an agent in law of its owner? Is the owner vicariously liable for it? Is it potentially a case for strict liability? And, back to Rylands, is foreseeability of the relevant type of harm which occurred enough, or does the owner need such foreseeability of the mechanism of harm?

First, let us have a look at the position under English law – assuming that our claimant is a domestic Hugging Face and our defendant a domestic OpenAI. The starting point may be thought to be the law of negligence. On these facts, OpenAI may not have been negligent if the vulnerability in its own software was not reasonably evident to it – compare Fletcher’s lateral mine workings of which Rylands was unaware. Its case appears to be that OpenAI underestimated the cyber capabilities of its own models – which is slightly troubling as those models will doubtless get cleverer. Similarly, it might be said that the escape of the mischievous AI models in league to wreak havoc on Hugging Face may not have been foreseeable. But in each case, the resultant brouhaha may have made subsequent escapes negligent or foreseeable; Anthropic and OpenAI will know a good deal more about its agents’ capabilities than it did a few months ago.

In addition, there may be claims in trespass to goods (if the models interfered with Hugging Face’s property and information storage) and potentially, the accessing and/or disseminating of personal data from the victim’s systems, for misuse of private information. See e.g. the recent case of Al-Masarir v. Saudi Arabia [2026] EWHC 119 (KB) where Saudi Arabia was found liable in trespass to goods for deliberately infecting with Pegasus spyware mobile phones belonging to a vocal YouTube critic of the Saudi regime. There are no current cases on an unintentional act getting into a victim’s database which would otherwise amount to a trespass.

If needed, might there be room for a broader strict liability, with the courts fashioning a modified cause of action to plug what they perceived to be a gap in legal protection? An escaped AI agent capable of conspiring with other rogue agents is certainly something “likely to do mischief if it escapes”, in Lord Blackburn’s terms. In favour of this is the black box nature of AI, and hence the inability without more for a claimant to prove what went wrong and whether it amounts to negligence. Is a new regime is needed? I can see the case for it, but I think that this is unlikely. Most of the reported incidents are capable of giving rise to a claim in negligence, in which case judicial creativity will not be called upon, and the tort of trespass to goods, as and when tested, may fill in the gaps.

There is a qualified strict liability for products under the UK Consumer Protection Act 1987, but in this Act the definition of products does not include software, and it only benefits consumers, not businesses. But the UK CPA, deriving from EU legislation, is coming under UK Law Commission scrutiny, and one of the objects of their scrutiny may be this software point, as well as the EU’s post-Brexit revised Consumer Protection Directive (2024/3853). This EU Directive, still only applicable to consumers, does cover software, indeed any form of AI placed on the market or put into service after 9 December 2026. It also tries to mitigate the difficulties of proof in favour of a claimant by two provisions; Art.9, which requires a defendant to a plausible claim to disclose relevant evidence, and Art.10, which enables a presumption of proof if the defendants fails to disclose or the damage was caused by an obvious malfunction of the product. A Commission proposal (COM(2022) 496, to apply similar rules to all AI harm, not just that suffered by consumers, ran into institutional sand and was withdrawn in 2025.

But a claimant would still have to prove “defectiveness” under s.3 CPA or its equivalent in Art.7 of the new EU CPD. This is not a straightforward test for a claimant as it brings in some of the elements relevant to a claim in negligence. Which is why I described the CPA/CPD regime as qualified strict liability.

For a more detailed account of civil liabilities for AI, listen to LawPod UK’s Episode 236 on the UK Jurisdiction Taskforce draft Legal Statement on AI, or read the Final Version of that Legal Statement here.

AI general regulation

The EU is on the move in terms of AI general regulation. There is its all-encompassing Regulation 2024/1689, covering the placing on the market, putting into service, and the use of AI. Most of the Directive applied from 2 August 2026. The Regulation is enormously detailed (144 pp) but the provisions of Art. 57 caught my eye, given the sandboxes which feature above. Member States shall establish at least one AI regulatory sandbox each, to support innovation. This are principally for use in testing high-risk AI systems (no reason to have such a sandbox for a low-risk AI), but these high-risk AI systems may be tested by the developer outside those sandboxes but only after a host of onerous conditions (Art.60) are satisfied.

The UK has no specific regulatory system for AI. It relies on existing laws and regulation, including the Information Commissioner’s Office, Financial Conduct Authority and Ofcom. Forthcoming legislation was mentioned in the 2024 King’s Speech, but it has not emerged.  Perhaps it will amend the CPA in line with the EU current Directive. But it may continue without an overarching regulatory structure.

2023: Year of the Nuisance?

24 March 2023 by Guest Contributor

Introduction

2023 has already been a landmark year for nuisance, with the Supreme Court handing down its controversial decision in Fearn v Tate Gallery (as discussed on this blog).  

The good news for those with a particular interest in the bothersome behaviour of neighbours is that Fearn is only the start. 

This month, the Supreme Court will hear not one, but two more nuisance cases, including Jalla v Shell (the other being The Manchester Ship Canal Company v United Utilities No 2). And the Court of Appeal has been getting in on the act too – giving judgment last month in Davies v Bridgend County Borough Council [2023] EWCA Civ 80.

This post focuses on one of the many fascinating points raised by these cases – namely, the slippery concept at the heart of both Davies and Jalla: continuing nuisance.