Cover：Strict Liability（Rylands v. Fletcher原則）／Vicarious Liability／Volenti non fit injuria／Causation（but for test, novus actus interveniens, Eggshell Skull Rule）／Remoteness of Harm（Re Polemis → Wagon Mound判例変更）
0. Where We start: Fault-Based Torts vs. Strict Liability
Fault-based liability: the tortfeasor is held liable because the act was committed intentionally or negligently
Strict liability: liability arises regardless of the doer’s intention or negligence
1. Strict Liability
1.1 Liability imposed without fault.
This typically arises where a dangerous thing escapes from land and causes damage the Rylands v Fletcher principle.
1.2 Why Strict Liability exists
Original reason: Discourage needless harm by forcing people to take every possible precaution
Modern reason: In the industrial age, it is often difficult for victims to prove fault on the part of manufactures
2. The Leading Case: Rylands v Fletcher (1868)
2.1 Facts
- Rylands (defendant) engaged independent contractors to build a reservoir on his land to supply water to his steam-powered textile mill.
- During construction, the contractors discovered disused mines beneath the land, with coal shafts loosely filled with soil and debris — but continued the work regardless.
- The reservoir burst, flooding the adjoining mine owned by Fletcher (plaintiff).
- Fletcher sued in negligence.
2.2 What each court decided
| Court | Contractors | Rylands (employer) |
|---|---|---|
| Trial court | Negligent (they knew about the old shafts) | Not negligent (he had no knowledge of the shafts) |
| Court of Exchequer Chamber | — | Liable regardless of knowledge or fault (strict liability) |
| House of Lords | — | Affirmed |
2.3 Blackburn J’s famous formulation (“the Rylands Rule”)
“…the person who for his own purposes brings on his lands and collects and keeps there anything likely to do mischief if it escapes, must keep it in 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.”
Keyword: “Dangerous Thing.”
2.4 The House of Lord’s key holding
The occupier was liable even if the escape of the dangerous thing accumulated on the land was not caused by the occupier’s negligence or intention. It is NOT open to the owner or occupier to escape liability by proving the absence of negligence or intention. → Strict Liability.
3. Expanding the Rylands Rule: From “Dangerous Things” to “Dangerous Acts” and “Dangerous Activities”
| Category | Examples |
|---|---|
| Dangerous living beings | Animals owned or possessed |
| Dangerous substances or materials | Escape of waste or toxic materials |
| Inherently / abnormally dangerous activities | Fireworks displays (pyrotechnics), nuclear power plants, rock blasting with dynamite |
| Defective products | Now governed by Product Liability legislation |
4. How Other Common Law Jurisdictions Reacted (Comparative Law)
4.1 Jurisdictions that keep the strict Rylands rule
- India: judicial strict application.
- United States: many states rejected the rule outright, but the trend — captured in Restatement (Third) of Torts §20(b) (2009) — is to preserve strict liability only for the defendant’s “ultrahazardous activity.”
4.2 Jurisdictions that reject Rylands as an independent tort
- Australia: Burnie Port Authority v General Jones Pty Ltd [1994] HCA 13
- Facts: BPA (defendant) allowed an independent contractor to carry out welding on its premises. The fire, caused negligently, spread to a nearby property and damaged the plaintiff’s frozen vegetables.
- Causes of action pleaded: nuisance, negligence, and strict liability under Rylands.
- Held: the Rylands rule involved “quite unacceptable uncertainty” and should be abolished.
- Rylands is not an independent head of tort liability but has been absorbed by the principles of ordinary negligence.
- New structure: a person who introduces a dangerous substance or activity onto premises owes a duty of care to avoid reasonably foreseeable risk of injury to others.
Related Thai case law
- Ang Hock Tai v Tan Sum Lee & Anor [1957] 23 MLJ 135: petrol (a dangerous substance) stored on the ground floor caught fire and spread upstairs → strict liability affirmed.
- Tesa Tape Asia Pacific v Wing Seng Logistics [2006]: containers stacked up to seven tiers collapsed. This case illustrates the possible overlap between nuisance and Rylands: stacking containers is not inherently “dangerous,” but stacking them far higher than usual, in the circumstances of the case, could be — a good example of the distinction between “dangerous by nature” and “dangerous in circumstances.”
- Cambridge Water Co v Eastern Counties Leather Plc [1994] 2 AC 264 (HL): a chlorinated solvent (PCE) seeped into the ground and, over 1.3 miles, contaminated a borehole used for drinking water.
- Issue: liability in both Rylands strict liability and nuisance.
- Held: introduced, for the first time, “foreseeability of harm” as a requirement for liability in nuisance. Since the solvent’s harmful potential was unforeseeable at the time, both claims failed.
- Important theoretical note: the House of Lords also judicially suggested that the Rylands rule is a subset of nuisance, rather than an independent tort.
- PEX International Pte Ltd v Lim Seng Chye and another [2019] SGCA 82 (Singapore): welding works on adjoining premises, carried out in strong winds and in the absence of proper supervision, ignited flammable material stored nearby.
- Negligence: the contractor’s selection was not negligent → claim failed (independent contractor delegation, similar in structure to Thai CCC s. 428).
- Nuisance: the works — carried out with the presence of strong winds and flammable material nearby — amounted to an “unreasonable use of land” → claim succeeded.
- Strict liability (Rylands): the activity amounted to a “non-natural use of the land” plus the escape of a “dangerous thing” → claim succeeded.
5. “Dangerous by Nature” vs. “Dangerous in Circumstances”
- Dangerous by Nature: the thing itself is inherently dangerous (explosives, wild animals
- Dangerous in circumstances: the thing is not inherently dangerous, but becomes so depending on the situation.
Example: water leaking from a pipe onto the floor of a building housing an art gallery — ordinarily harmless “water” could, in such circumstances, be treated as a “dangerous thing.”
6. US Law: Restatement of Torts §520 (Factors for “Abnormally Dangerous” Activity)
Factors relevant to whether an activity is “abnormally dangerous”:
- Existence of a high degree of risk of some harm to person, land, or chattels.
- Likelihood that the harm resulting from it will be great.
- Inability to eliminate the risk by the exercise of reasonable care.
- Extent to which the activity is not a matter of common usage.
- Inappropriateness of the activity to the place where it is carried on.
- The extent to which its value to the community is outweighed by its dangerous attributes.
Applying the test: Miller v Civil Constructors, Inc. 651 N.E.2d 239 (Ill. App. 1995)
- Police officers held target practice at a firing range on a quarry owned by the defendant. A stray bullet struck Miller (plaintiff) and made him fall from a truck.
- Held: the defendant was NOT liable. Reasoning: the social utility of target practice by law enforcement officers — improving their weapon skills — outweighed the dangers involved.
7. Are Defences Available Against Strict Liability?
| Type | Defence available? |
|---|---|
| Common law strict liability (Rylands rule) | No defence for the tortfeasor |
| Statutory strict liability | Some statutes allow limited defences. Example: under Product Liability (PL) legislation, a manufacturer may escape liability if it proves the defect was not known to it at the time |
| Exception: certain environmental statutes | No defence at all, e.g. for crude oil spills that leak and flow to the sea, the possessor is liable irrespective of his fault |
8. Strict Liability under Thai Law (Comparative Portion of the Lecture)
| Provision | Content (summary) |
|---|---|
| s. 433 CCC | Damage caused by an animal → owner/keeper liable unless reasonable care is proven (a presumption of fault) |
| s. 436 CCC | Damage from a thing falling out of a building, or improperly thrown → residents liable (within the “tort provisions”) |
| s. 437 CCC | The possessor/controller of a mechanically operated vehicle is liable, unless the damage results from force majeure or the injured person’s own fault. Para. 2: this rule also extends to a person in possession of a thing that is “dangerous by its nature, or by its intended use or operation” — i.e., a quasi-Rylands rule |
9. Vicarious Liability
9.1 Definition
A person (A) may be liable for a tortious act committed by a third person (B), where B is judicially regarded as having a special relationship with A.
A can be liable even without any fault of A’s own, purely because of the nature of A’s relationship with B.
9.2 Which relationships qualify
| Relationship | Vicarious liability? |
|---|---|
| Employer – Employee (in the course of employment) | YES (cf. Thai CCC s. 425) |
| Principal – Agent | YES (cf. Thai CCC s. 427) |
| Employer – Independent Contractor | NO, in principle (cf. Thai CCC s. 428) |
10. Volenti non fit injuria
Volenti non fit injuria = “to a willing person, no injury is done.”
Where the injured person consents to the injurious act, the law takes it for granted that there is no injury caused. Hence, no claim in tort.
Example: a spectator at an ice hockey match who is injured by a puck flying out of the rink in the course of play cannot claim damages, because they are treated as having accepted that risk as an inherent part of watching the game.
10.2 Requirement: the acceptance must be “voluntary”
Morris v Murray [1990] 3 All ER 801 (CA)
- Facts: the plaintiff accepted a plane lift from a drunk pilot, and even helped him start the engine and tune the radio.
- Outcome: the plane crashed and the pilot died. The surviving passenger sued the pilot’s estate, arguing that he had not voluntarily consented to the risk involved in flying, since he was not drunk enough to fail to realize it.
- Held: the passenger was not so drunk as to fail to realize the risks of taking a lift from a drunk pilot → the volenti non fit injuria rule applied (claim barred).
Nettleship v Weston [1971] 3 All ER 581 (CA)
- Facts: the plaintiff (N), a driving instructor, was injured due to the driving learner’s (Mrs. W’s) lack of skill and experience.
- Issue: did N voluntarily accept for himself the risk of injury arising from the driver’s lack of skill and experience?
- Held: there was no evidence that N had voluntarily accepted the risk of injury. On the contrary, his inquiry concerning the comprehensiveness of Mrs. W’s insurance policy was a positive indication that he had not voluntarily accepted the risk → volenti did not apply (N could recover).
11. Causation
11.1 Where it fits
Causation is a required element common to both major categories of tort (Intentional Tort and Negligence):
Intentional Injurious Act → [Causation] → Damage
Negligence: Duty of Care → Breach of Duty → [Causation] → Damage → Tort of Negligence11.2 Definition
Proof that the tortious act is the cause of the damage. In other words, the damage is the consequence of the tortious act.
11.3 The “But For” Test (test for factual causation)
Where it is proved that but for (in the absence of) the defendant’s tortious act, the damage would not have occurred, it can be concluded that the damage was actually caused by the defendant’s tortious act. Conversely, where it is proved that but for the defendant’s tortious act, the damage would nonetheless have occurred, then the damage was NOT caused by the defendant’s act, but by some other cause. → Multiple Causes of Damage
🇯🇵 Comparison with Japanese law
Japan’s test for factual causation is essentially the same “but-for” formula (“あれなければこれなし” — “without this, not that”), used in judicial practice much as it is here. Japan, however, traditionally splits the inquiry into two stages: factual causation, followed by proximate/adequate causation (相当因果関係) — drawing on Civil Code Art. 416 by analogy, and adopted by case law. This second stage corresponds closely to the “remoteness of harm” discussion below (the “reasonably foreseeable” standard in English law).
11.4 Multiple Causes of Damage
| Term | Meaning |
|---|---|
| Causa causans | The immediate cause, without which the event would not have occurred (a “direct cause”) |
| Causa sine qua non | A cause that, though not a direct cause, contributed to the damage (a “contributing cause”); may amount to a novus actus interveniens (new intervening act) |
11.5 Intervening Acts (novus actus interveniens) and the Breaking of the Causal Chain
| Situation | Rule |
|---|---|
| The victim’s own unusual physical trait | The tortfeasor is always liable (→ Eggshell Skull Rule / Thin-Skull Rule, discussed below) |
| An intervening cause other than the victim’s own trait, which is not foreseeable | The tortfeasor is NOT liable — the intervening cause breaks the chain of causation |
Illustrations:
- A victim who has been attacked dies of lightning while being carried to hospital for treatment → the attacker is NOT liable for the death (the intervening event was unforeseeable).
- A victim who has been attacked dies as a result of negligent medical treatment → case law generally treats negligent treatment as foreseeable, so the attacker remains liable in most circumstances.
11.6 The Eggshell Skull Rule (Thin-Skull Rule)
“You have to take your victims as you find them.”
The principle: even if the tortfeasor only intended to inflict simple bodily harm on an ordinary person, if the victim in fact had an exceptionally thin skull (or some other unusual physical trait), and this led to death or serious injury, the tortfeasor is liable for the full extent of the harm.
Rationale: public policy. Courts do not want a defendant to escape liability by relying on the victim’s own vulnerability.
Smith v Leech Brain & Co. [1962] 2 QB 405
- An employee at a factory was splashed with molten metal, burning his lower lip.
- The tissue at the site of the burn had a pre-malignant condition (abnormal cells associated with increased risk of cancer).
- The burn triggered cancer, and the employee died.
- Held: even though the development of cancer was itself unforeseeable, the tortfeasor “takes his victim as he finds him,” and is liable.
Page v Smith [1995] 2 WLR 644 (HL)
- Mr. Page was involved in a minor car accident. He was not physically injured, but the collision resulted in a recurrence of his pre-existing disease (myalgic encephalomyelitis, or chronic fatigue syndrome (CFS)), from which he had been in remission for 20 years.
- Mr. Page became unable to return to his job as a teacher.
- Question: Was the defendant liable for this psychiatric injury?
- Answer: YES — an important case extending the Eggshell Skull Rule to psychiatric/psychological harm.
Vosburg v Putney, 80 Wis. 523, 50 N.W. 403 (Wis. 1891) (US)
- An 11-year-old boy slightly kicked a 14-year-old boy in the shin at school. The victim did not feel it immediately, but later felt extreme pain, caused by previous injury at the same spot on the leg.
- The kick resulted in the boy’s total loss of use of his limb.
- Held: since the kick occurred inside the classroom rather than on the playground, it was unlawful and constituted a battery. The 11-year-old boy was liable for the victim’s total loss of use of the leg. “Takes his victim as he finds him.”
🇯🇵 Comparison with Japanese law
There is no exact codified equivalent of the Eggshell Skull Rule in Japan, but Japanese case law frequently discusses damages reduction for pre-existing vulnerabilities (素因減額) where a claimant’s psychological or physical predisposition contributed to the extent of harm. Notably, Japanese case law (e.g., the Supreme Court decision of 25 June 1992) takes the position that, on grounds of fairness, damages may be reduced where the claimant’s own predisposition — physical or psychological — contributed to the extent of the harm. → This is an important and non-obvious point: while English law (via the Eggshell Skull Rule) generally imposes full liability and does not reduce damages for the victim’s own predisposition, Japanese law moves in essentially the opposite direction, permitting a reduction by analogous application of Civil Code Art. 722(2). Being able to state this contrast clearly is worth remembering for exams and essays.
11.7 The Eggshell Skull Rule Applied to Other Torts
The rule applies also to other categories of torts, e.g. Trespass.
Example: if a trespasser’s wrongful presence on the victim’s property so terrifies the victim that the victim has a fatal heart attack, the trespasser will be liable for the damage stemming from the original tort.
11.8 Intervening Causes Not Concerning the Victim’s Trait: Lamb v London Borough of Camden [1981] 2 All ER 408
- Facts: workers of the London Borough of Camden struck a water pipe, which caused serious damage to the claimant’s house’s foundation. The tenant had to move out during her stint in America.
- One year later, squatters moved in and caused further, additional damage.
- Issue: was the Borough liable for this further damage caused by the squatters (i.e., was the ruin regarded as caused by the Borough’s tortious act)?
- Held: the Borough was NOT liable for the acts of the squatters. Such an act by a third person (novus actus interveniens) was not foreseeable and would break the chain of causation.
- Note: some judges considered the squatters’ act as not foreseeable, but held that the Borough was not liable on a “public policy” ground — namely, that insurance was more appropriately the provider of funds in such a case.
12. Remoteness of Harm
12.1 The basic framework
Even if the harm is caused by the tortfeasor’s wrongful act based upon the but-for test, the courts may still deny compensation if the “extent of harm” is a very remote consequence of the initial wrong.
That is: even where causation is established, if the “extent” of the damage is far too unforeseeable, compensation is limited.
A tortfeasor is liable only for the probable consequences of his act — i.e., liable only for harm that is not too remote.
🇯🇵 Comparison with Japanese law (key point)
This maps directly onto Japan’s doctrine of adequate/proximate causation (相当因果関係論), and more specifically onto the scope-of-damages rule under Civil Code Art. 416 (applied by analogy to tort, per case law and prevailing academic theory). That is:
- Japanese law: damages are limited to (i) “ordinary” damage naturally arising from the breach (Art. 416(1)), and (ii) “special” damage arising from special circumstances, but only if such circumstances were foreseeable (Art. 416(2)).
- English law: damages are limited to loss that was “reasonably foreseeable” (the Wagon Mound principle).
Though phrased differently, both systems serve the same function: preventing unlimited liability by capping the scope of recoverable damages using a foreseeability standard. This correspondence is one of the most important comparative-law points to remember.
12.2 The Evolution of the Case Law: From Re Polemis to The Wagon Mound (No. 1)
Re Polemis & Furniss, Withy & Co. [1921] 3 K.B. 560 (the old rule)
- Facts: an employee of the charterer negligently dropped a heavy wooden plank into the ship’s hold.
- The falling plank caused a spark, which ignited vapour from benzene stored in the hold, causing an explosion that resulted in the total destruction of the ship.
- Held: the defendant was liable for the entire damage, even though the “extent” of the fire damage was not reasonably foreseeable (too remote). Rule: where the damage is a consequence of the culpable act, the tortfeasor is liable for all the damage, irrespective of whether the extent of the damage is foreseeable or not.
- → This rule was felt to be unfair and was subsequently overruled by The Wagon Mound.
The Wagon Mound (No. 1) [1961] AC 388 (the new rule; Privy Council)
- Facts: Overseas Tankship’s ship, the Wagon Mound, docked in Sydney Harbour in October 1951. The crew carelessly allowed furnace oil to leak from the ship.
- The oil spread over the water to the plaintiff’s wharf, where the plaintiff was carrying out metal welding work.
- Molten metal fell onto floating cotton waste on the water, which ignited it. The fire further ignited the furnace oil, and the wharf and two ships moored there sustained substantial fire damage.
- Held: the defendants were NOT liable, because:
- They did not know, and could not reasonably have been expected to know, that the oil was capable of being set alight when it spread on water. [The extent of harm was too remote.]
- Furnace oil had such a high boiling point that it was unlikely to catch fire under normal circumstances, and the dock owners knew the oil there would not burn on water.
- Key holding: “It is a principle of civil liability, subject only to qualifications which have no present relevance, that a man must be considered to be responsible for the probable consequences of his act. To demand more of him is too harsh a rule, to demand less is to ignore that civilised order requires the observance of a minimum standard of behaviour.” → Re Polemis was overruled.
The Wagon Mound (No. 2) [1967] 1 AC 617 (Privy Council)
- Same fire, but brought by a different claimant — the owners of the two ships damaged in the fire.
- Trial judge: the defendant was NOT liable, given that the risk of the oil catching fire on water was low, and thus the damage (the loss of the wharf and the ships) was not reasonably foreseeable.
- Privy Council: the defendant WAS liable, because a reasonable person would have been aware of the risk of fire caused by the ignition of the furnace oil, even if the probability of that fire risk was low (unless it happens only in very exceptional circumstances).
- “It follows that in their Lordships’ view the only question is whether a reasonable man, having the knowledge and experience to be expected of the chief engineer of the Wagon Mound, would have known that there was a real risk of fire in some way.”
🇯🇵 Practice point
Wagon Mound (No. 1) and (No. 2) concern the same accident, yet the outcomes for different claimants were reversed — an extremely important practical lesson. In other words, foreseeability is heavily dependent on the evidence presented and how the case is argued — not simply an abstract legal test. It’s the litigation strategy and quality of the factual evidence presented that can decide the outcome, as much as the underlying rule itself.
Summary: Key Points from Week 4 (Practice / Exam Focus)
- Strict liability under the Rylands rule is genuinely “no-fault liability.” Proof of fault is unnecessary, and almost no defences are available — the single most distinctive feature of this doctrine. Japanese law has no comparable general doctrine; it instead achieves similar results through specific legislation (Arts. 717, 718, PL Act, etc.).
- Different jurisdictions have taken divergent approaches to the Rylands rule — retained (UK, Singapore, Thailand), absorbed into negligence (Australia), and limited to ultrahazardous activities (US). Always organize a comparative-law answer by jurisdiction and position.
- For vicarious liability, the key dividing line is between employer–employee/principal–agent (liability applies) and independent contractor (liability generally does not apply) — this is the single most important test (compare Japan’s Civil Code Arts. 715–716). Note the important exception where there was negligence in selection or supervision (Art. 716 proviso; Thai s. 428).
- Volenti non fit injuria requires voluntary consent. Mere awareness of a risk is not enough — courts look for concrete evidence of consent and acceptance of risk (e.g., whether the person made insurance-related inquiries).
- Causation (the but-for test) and remoteness of harm (foreseeability) are separate requirements — do not conflate them. Even where causation is established under the but-for test, damages may still be limited if the extent of harm is too remote (the Wagon Mound principle).
- The Eggshell Skull Rule (where the victim’s physical trait exacerbates the harm) leads to full liability for the tortfeasor — an outcome that is, importantly, the opposite of Japan’s case-law doctrine of damages reduction for pre-existing vulnerability. Be prepared to state and explain this contrast clearly.
