Negligence - Causation and Remoteness
For the role played by policy in the issue of causation, see the speech of Lord Denning.
CAUSATION IN FACT
BUT FOR TEST
The claimant must prove that harm would not have occurred 'but for' the negligence of the defendant.
It is possible to apply the 'but for' test where there is speculation as to how the claimant would have behaved in a given situation.
The question of causation may also arise where there is a dispute about what the defendant would have done in a given situation.
Sometimes, it may be clear that the defendant's breach of a duty did not actually cause the harm suffered by the claimant.
PROOF OF CAUSATION
The claimant must prove, on the balance of probabilities, that the defendant's breach of duty caused the harm. The defendant does not have to provide an explanation for the cause of harm but a failure to do so may be a factor in deciding whether the claimant's explanation of the cause should be accepted.
However, the claimant does not have to prove that the defendant's breach of duty was the main cause of the damage provided that it materially contributed to the damage.
It may be sufficient for the claimant to show that the defendant's breach of duty made the risk of injury more probable.
Where there are a number of possible causes, the claimant must still prove the defendant's breach of duty caused the harm or was a material contribution.
Where the claimant's case is based on proving a material contribution to the damage, the defendant is responsible only for that part of the damage to which his negligence has contributed.
The case of McGhee has also been applied to a case where there were three possible causes of injury.
LOSS OF CHANCE
A claimant may lose because of a solicitor's negligence an opportunity to bring legal proceedings, or because of a doctor's negligence a good chance of recovery. Loss of chance is actionable in contract (Chaplin v Hicks  2 KB 786) but its extent in tort is unclear.
The House of Lords have held that questions of loss of chance do not arise where there are positive findings of fact on the issue of causation. Such a case may be an 'all or nothing' case.
Where the claimant's loss resulting from the defendant's negligence depended on the hypothetical action of a third party, either in addition to action by the claimant or independently of it, see the decision of the Court of Appeal.
The Court of Appeal has followed the approach adopted in Allied Maples in two later cases: First Interstate Bank v Cohen Arnold & Co  1 PNLR 17, and Stovold v Barlows  1 PNLR 91
INADEQUACY OF THE BUT FOR TEST
The but-for test will be inadequate in a number of cases, for example, where the breach of duty consists of an omission to act, where the claimant's damage is the result of more than one cause and where the claimant's loss is economic.
CAUSATION IN LAW
causa causans = immediate or effective causecausa sine qua none = ineffective causenova causa interveniens = new intervening causenovus actus interveniens = new act intervening
Where there are two successive causes of harm, the court may regard the first event as the cause of the harm.
However, it is possible for a second supervening event to reduce the effect of a tort.
Where a tort is submerged in a greater injury caused by (a) another tort or (b) a supervening illness or non-tortious event.
NOVUS ACTUS INTERVENIENS
ACTS OF THIRD PARTIES
The defendant may be responsible for harm caused by a third party as a direct result of his negligence, provided it was a highly likely consequence.
ACTS OF THE CLAIMANT
If the claimant suffers further injury as a result of his own actions, there will be a break in the chain of causation only if the claimant acted unreasonably.
A defendant may be responsible where the claimant commits suicide following the defendants' negligence. However, damages will now be apportioned under the Law Reform (Contributory Negligence) Act 1943.
Public policy will prevent a claimant relying on his own criminal acts from seeking compensation from the defendant.
REMOTENESS OF DAMAGE
THE CONTRASTING APPROACH OF THE APPELLATE COURTS
The opinion of the Court of Appeal was that a defendant was liable for all the direct consequences of his negligence, no matter how unusual or unexpected:
Re Polemis  3 KB 560
The opinion of the Privy Council was that a person is responsible only for consequences that could reasonably have been anticipated.
MANNER OF OCCURRENCE
If harm is foreseeable but occurs in an unforeseeable way there may still be liability.
However, there are two cases which go against this decision:
TYPE OF HARM
The damage must be of the same type or kind as the harm that could have been foreseen.
Note that only personal injury of some kind needs to be reasonably foreseeable where a primary victim suffers psychiatric harm.
EXTENT OF HARM
The defendant will still be liable, provided the type of harm and its manner was reasonably foreseeable, if the extent of the harm was not foreseeable.
It is well-established that 'The tortfeasor must take his victim as he finds him'. The defendant will be responsible for the harm caused to a claimant with a weakness or predisposition to a particular injury or illness.
The claimant's impecuniosity (lack of funds) is no excuse for a failure to mitigate damages. See the decision of the House of Lords in:
Liesbosch Dredger v SS Edison  AC 449
However, this authority has been distinguished by the Court of Appeal, QBD and the Privy Council:
Alcoa Minerals v Broderick  3 WLR 23