Part B The law of obligations 7: The law of torts and professional negligence 111
5.2.1 Multiple causes
The courts often have difficulty in determining causation where there are a number of possible causes of
injury including the negligent act. The courts must decide on the facts if the negligent act was the one that
most likely caused the injury.
Wilsher v Essex AHA 1988
The facts: A premature baby suffered blindness after birth. It was claimed that a doctor failed to notice that
the baby received high doses of oxygen and this caused the blindness.
Decision: Evidence was provided that there was six possible causes of the blindness including the one
claimed. However, the court could not ascertain which of the six actually occurred and therefore could not
create a direct causal link.
The case below indicates the court's flexibility when applying legal principles in exceptional cases.
Fairchild v Glenhaven Funeral Services Ltd & Others 2002
The facts: The claimants all contracted a disease caused by contact with asbestos over extended periods
of time with several different employers. The defence claimed that the disease could be contracted by
exposure to one asbestos fibre and as the claimants were employed by a number of employers it could not
be established at which employer they contracted the disease.
Decision: The House of Lords held that all the employers (who had failed to take reasonable care),
contributed to the cause and were all liable.
5.3 Novus actus interveniens
Courts will only impart liability where there is a cause of events that are a probable result of the
defendant's actions. Defendant's will not be liable for damage when the chain of events is broken. There
are three types of intervening act that will break the chain of causation.
5.3.1 Act of the claimant
The actions of the claimant themselves may break the chain of causation. The rule is that where the act is
reasonable and in the ordinary course of things an act by the claimant will not break the chain.
McKew v Holland, Hannen and Cubbitts (Scotland) Ltd 1969
The facts: The claimant had a leg injury which was prone to causing his leg to give way from time to time.
Whilst at work he failed to ask for assistance when negotiating a flight of stairs. He fell and was injured as
a result.
Decision: The fact that the claimant failed to seek assistance was unreasonable and was sufficient to break
the chain of causality.
5.3.2 Act of a third party
Where a third party intervenes in the course of events the defendant will normally only be liable for
damage until the intervention. For example, in Knightley v Johns 1982 the defendant caused a road traffic
accident. A police inspector negligently handled traffic control following the accident. This negligence led
to the claimant, a police officer, being killed. The defendant who caused the accident successfully argued
that the negligent handling by the police inspector broke the chain of causation between his negligence
and the death of the officer.