Exam Notes for Tort Law B

01 CAUSATION, JOINT & SEVERAL LIABILITY & THE DEFENCES OF
CONTRIBUTORY NEGLIGENCE & VOLENTI NON FIT INJURIA

Causation in fact
1. Basic principles
 C must show on a balance of probabilities that D’s act / omission was in fact a
cause of C’s harm
 However, ultimately driven by policy considerations & the courts will take a
pragmatic approach to achieve justice
 General test: “But for” – But for D’s conduct, C’s loss wouldn’t have occurred
- Consider the hypothetical / counterfactual scenario that would probably have
happened had D acted carefully
 Barnett v Chelsea & Kensington Hospital Management Committee: C
would’ve died anyway having drunk the arsenic so the doctor’s failure to
examine him wouldn’t have made a difference  But for test failed (existing
cause)
 McWilliams v Sir William Arrol: C would’ve been injured anyway even if the
safety belts had been provided  But for test failed (hypothetical cause)
 Bolitho v City & Hackney HA: D is not allowed to rely on any
hypothetical conduct on his part that would’ve been negligent

 Where D’s wrong is a “but for” cause, but combines with other factor(s) to cause the
harm  D will be held liable on the basis of having made a “material contribution”
(Bonnington Castings v Wardlaw)
 C may be able to establish “but for” causation by relying on statistical evidence that
shows that D’s wrong more than doubled the risk of harm (Sienkiewicz v Grief)
- Fact: C contracted mesothelioma  D was only 18% to blame for the initial
exposure
- Held: D liable in full
- Principle: “Doubles the risk” test – Applies epidemiological data to determine
causation on a balance of probabilities in circumstances where medical science
doesn’t permit determination with certainty of how & when an injury was caused
 Ratio: If statistical evidence indicates that the intervention of a wrongdoer
more than doubled the risk that the victim would suffer the injury  It is
more likely than not that the wrongdoer caused the injury
- Jones v SoS for Energy & Climate Change: D held not liable as not twice as
likely to have caused C’s disease than any other factors
- Williams v Bermuda Hospitals Board: The test is not an exercise to be applied
mechanistically (a doubled tiny risk will still be very small)

2. Proof of causation
 “All / nothing” approach
- General straightforward “but for” test
- C must show on a balance of probabilities that D’s breach (rather than some other
event) caused the loss
- Hotson v East Berkshire AHA  Gregg v Scott  Wilsher v Essex AHA (see (6)
for facts)

,  “Material contribution” approach
- Bonnington Castings v Wardlaw
 Fact: C contracted a lung disease from a cumulative combination of non-
tortious & tortious dust from his workplace, of which the tortious dust was in
the minority
 Held: D liable (the tortious dust contributed to a tipping point towards
contracting the disease)
 Principle:
 Onus lies with C to prove that D’s fault on the balance of probabilities
materially contributed his injury (no need to show that it was the sole /
dominant cause)
 What is “material” is a question of degree on the facts of each case
- Bailey v MoD
 Fact: C was cared for negligently post-operation & resulted in brain damage
 Held: Hospital liable
 Principle: For cumulative cause cases which produce indivisible harm, where
medical science cannot establish the evidence needed to apply the “but for”
test  Sufficient to show that D’s conduct materially contributed to the injury
- McGhee v National Coal Board
 Fact: C contracted dermatitis due to D’s failure to provide washing facilities
 Held: D liable (material contribution)
 Principle: For cumulative cause cases, the mere presence of an above de
minimis tortious factor among the cumulative causes is enough
 The interpretation of “material contribution” as an exception to the “but
for” test
- Where there are cumulative causes, it matters not whether they are concurrent /
successive (Williams v Bermuda Hospitals Board)
- Where the harm is indivisible, D who has tortiously contributed to the cause will be
liable in full; Where the harm is divisible, D will be liable in respect of the share of
the harm for which he is responsible (Sienkiewicz v Grief)

 “Material increase in risk” approach
- McGhee v National Coal Board: Sufficient to show that D’s wrong materially
increased the risk of harm
- Doesn’t apply where D’s negligent act increases the risk of harm but there are
other (non-tortious) factors which may have caused the harm
 Wilsher v Essex AHA
 Fact: A baby was given excess oxygen by a junior doctor & suffered
eye condition as a result
 Held: D not liable (numerous possibilities)

3. Apportionment
 Where more than 1 D is liable for a particular harm  Each is liable in full for that
harm (the risk of insolvency is borne amongst Ds, not C)
 Where D’s wrong is not on its own sufficient but combined with a non-tortious factor
caused the harm  D is liable in full

,  Apportionment will not be justified in cases of a single indivisible injury

 Claims for the aggravation of an existing harm
- D2 is only liable for the additional loss he has caused

 Claims for the advancement of a harm that would’ve occurred non-tortiously at a
later date (Bonnington Castings v Wardlaw)

 Claims where separate negligent acts of D1 & D2 each caused a distinct harm to C
- Rahman v Arearose
 Fact: An employee was assaulted at work & sustained eye injuries  A
hospital later negligently treated the eyes & caused blindness
 Held: Damages apportioned (distinct injuries)
 Principle: Whether the harms are distinct / divisible is a question of fact’

 A special apportionment rule has been adopted in the case of cumulatively caused
industrial injuries
- Holtby v Brigham & Cowan
 Fact: C was exposed to asbestos while for working for different employers
(including D for 12 years) & developed asbestosis (a disease that gets
progressively worse with on-going exposure)
 Held: D liable, but damages reduced (D only liable in proportion to the
exposure he had actually caused)
 Principle: Responsibility for the development of cumulatively caused
industrial diseases is divided between successive employers on a “time-
exposure” basis

 Claims in respect of indivisible injuries based on Fairchild: A further special
apportionment rule applies here
- Fairchild v Glenhaven Funeral Services
 Fact: C contracted mesothelioma (the risk of which cannot be attributed
cumulatively) having worked for different employers
 Held: All employers jointly liable (material increase in risk, not cumulative)
 Affirmed McGhee v National Coal Board
- Barker v Corus
 Fact: C contracted mesothelioma due to exposure to asbestos in the course
of employment with several employers & self-employment
 Held: Fairchild applies even where there is a period of self-employment
 However, cases like Fairchild should impose several liability, not joint
liability  Apportionment  Overruled by Compensation Act 2006, s
3 in relation to mesothelioma cases but still applies to non-
mesothelioma cases (Heneghan v Manchester Dry Docks)

 Compensation Act 2006, s 3
- Damages are not to be apportioned in mesothelioma cases
 D liable in full; Liability exists “jointly & severally” with any other D
responsible
- Confirmed in International Energy Group v Zurich Insurance