Causation

Causation

The claimant must establish a causal link (nexus) between the defendant’s breach of duty and the damage suffered.

Types of causation

Factual causation and legal causation.

Factual causation

Concerned with whether the defendant’s breach actually caused the claimant’s damage.

Legal causation

Concerned with whether the causal link should be regarded as broken due to intervening events (novus actus interveniens).

But-for test

On the balance of probabilities, but for the defendant’s breach of duty, would the claimant have suffered the loss at that time and in that way?

But-for test satisfied

If the damage would not have occurred without the defendant’s breach.

But-for test not satisfied

If the damage would have occurred anyway, even without the defendant’s breach.

Barnett v Chelsea and Kensington Hospital (1969)

Facts: A doctor negligently failed to examine a patient who later died from arsenic poisoning. Medical evidence showed the patient would have died even if examined. Held: The claim failed; factual causation was not established because death would have occurred anyway.

Balance of probabilities

The claimant must show it is more likely than not (over 50%) that the breach caused the damage.

Wilsher v Essex AHA (1988)

Facts: A premature baby became blind. There were five possible causes of blindness, only one of which was negligent oxygen treatment. Held: Causation failed; the claimant could not prove on the balance of probabilities that the negligence caused the injury.

Exceptional cases where but-for test fails

The courts may still find causation in limited circumstances such as material contribution or material increase in risk.

Material contribution test

Applied where multiple causes (tortious and non-tortious) operate together to cause the damage.

Bonnington Castings v Wardlaw (1956)

Facts: The claimant contracted pneumoconiosis from inhaling dust at work, some from negligent exposure and some from non-negligent sources. Held: The claim succeeded; the defendant’s breach materially contributed (more than negligibly) to the disease.

Material contribution meaning

A contribution that is more than negligible, not necessarily the sole or main cause.

Bailey v Ministry of Defence (2008)

Facts: The claimant suffered brain damage after choking on vomit due to weakened condition caused by both natural illness and negligent medical care. Held: Causation established; negligent care made a material contribution to the claimant’s weakened state leading to injury.

Material increase in risk test

Applied where medical science cannot prove which exposure caused the damage, but the defendant’s breach increased the risk of harm.

McGhee v National Coal Board (1973)

Facts: The claimant contracted dermatitis after exposure to brick dust at work. No breach in exposure, but breach in failing to provide washing facilities, leaving dust on skin longer. Medical evidence could not prove causation. Held: The claim succeeded; the defendant’s breach materially increased the risk of dermatitis.

Limits of material increase in risk

Generally confined to industrial disease cases involving scientific uncertainty.

Fairchild v Glenhaven Funeral Services (2003)

Facts: The claimant was exposed to asbestos by multiple employers and later developed mesothelioma. Science could not identify which exposure caused the disease. Held: Liability imposed; each employer had materially increased the risk of harm.

Mesothelioma and causation

Under s 3 Compensation Act 2006, defendants who materially increased the risk are jointly and severally liable.

Loss of chance doctrine

Generally not recognised for personal injury claims.

Hotson v East Berkshire HA (1987)

Facts: A child fell from a tree and suffered a hip injury. Negligent hospital treatment reduced his chance of recovery from 75% to 25%. Held: The claim failed; the injury was likely caused by the original fall, and loss of chance is not actionable in personal injury.

Loss of chance in pure economic loss

Recognised where there is a real and substantial chance of a better outcome.

Allied Maples Group v Simmons & Simmons

Facts: Solicitors negligently failed to advise on a contractual clause, causing loss of chance to negotiate better terms. Held: The claim succeeded; a real and substantial chance was lost.

Factual causation in failure to advise cases

A modified but-for approach applies.

Chester v Afshar (2004)

Facts: A surgeon failed to warn of a small but known risk of paralysis from surgery. The risk materialised. Held: Causation established because the claimant proved she would have deferred surgery if warned, and the injury would not have occurred at that time.

Legal causation

Requires determining whether the chain of causation has been broken by a novus actus interveniens.

Novus actus interveniens

A new intervening act that breaks the chain of causation between breach and damage.

Types of novus actus

Acts of God or natural events, acts of third parties, acts of the claimant.

Acts of God / natural events

Exceptional natural events that are unforeseeable and break the chain of causation.

Carslogie Steamship v Royal Norwegian Government (1952)

Facts: A ship damaged in a collision later suffered storm damage while sailing for repairs. Held: Defendant liable for collision damage but not storm damage; storm was a novus actus.

Acts of third parties

Subsequent acts break the chain only if they are independent, unforseaable, and so significant that it makes it unfair to blame the original defendnant

Knightley v Johns (1982)

Facts: After a road accident, a police officer negligently ordered traffic to drive the wrong way through a tunnel, causing further injuries. Held: The police officer’s negligence broke the chain of causation.

Medical treatment as a novus actus

Medical negligence will only break the chain if it is gross or unforeseeable.

Wright v Cambridge Medical Group (2011)

Facts: A GP negligently failed to refer a child; hospital treatment was also negligent, leading to permanent injury. Held: Chain not broken; hospital negligence was not so egregious as to destroy causation.

Acts of the claimant

The claimant’s conduct must be highly unreasonable to break the chain; usually dealt with as contributory negligence.

McKew v Holland & Hannen & Cubitts (1969)

Facts: After a leg injury caused by the defendant, the claimant descended stairs without a handrail and fell. Held: The claimant’s unreasonable act broke the chain of causation.

Wieland v Cyril Lord Carpets (1969)

Facts: Due to a neck brace caused by the defendant’s negligence, the claimant fell down stairs despite taking care. Held: The chain was not broken; defendant remained liable.

Performance Cars v Abraham (1962)

Facts: A Rolls-Royce required repainting after one accident; a second collision caused no additional damage. Held: Second defendant not liable as no additional damage was caused.

Baker v Willoughby (1970)

Facts: Defendant caused a leg injury affecting earning capacity; later the claimant was shot and the leg amputated. Held: First defendant remained liable for ongoing loss caused by original injury.

Jobling v Associated Dairies (1982)

Facts: Defendant caused a back injury reducing earnings; later the claimant developed an unrelated illness preventing work entirely. Held: Liability ceased at the onset of the illness; natural event broke the chain.

Legal causation summary

Courts draw a line where subsequent events make it unjust to attribute further loss to the defendant.