Causation and Defences
March 20, 2023
1 Factual Causation: But-For
• To establish that a breach of a duty of care caused damages, causation in
fact needs to be established.
• Like the notion of factual cause in criminal law, causation in fact is deter-
mined through the ‘but-for’ test.
• Barnett v Chelsea and Kensington Hospital Management Committee [1969]
1 QB 428 is a leading case on this; for it was shown that, but-for the de-
fendant’s breach of their duty of care to the claimant, the claimant would
still have died. Thus, the defendant’s breach of their duty of care to the
claimant was not causative of the claimant’s death.
• As tort falls under civil law, to establish causation, the claimant must
show that the harm suffered was caused by the defendant on the balance
of probabilities.
• In Hotson v East Berkshire Area Health Authority [1987] 2 All ER 909,
as the claimant could not prove on the balance of probabilities that the
defendant’s breach of their duty of care to them caused their injury, the
claim failed.
2 Factual Causation Again: But-For
• The question of causation can be much more difficult to answer when there
are several possible alternative causes of the claimant’s injury.
• For example, in Wilsher v Essex Area Health Authority [1988] AC 1074,
the evidence was that there were up to five causes of the victim’s injury.
And, as the claimant had not proven on the balance of probabilities that
the doctor’s negligence was the cause of the victim’s injury, the claim was
ordered for retrial.
1
, 3 Factual Causation: Material Contribution
• As the but-for test can fail where there are many causes of damage, such
as Wilsher, the courts can look for a different test to determine causation.
• In Bonnington Castings Ltd v Wardlaw [1956] AC 613, even though there
were two distinct causes for the damage, the claimant succeeded in estab-
lishing causation because he could show that the defendant’s breach of
duty materially contributed to the disease from which he suffered.
• McGhee v National Coal Board [1973] 1 WLR 1 is similar; even though
there were two distinct causes for the damage, the claimant succeeded
in establishing causation because they could show that the defendant’s
breach of duty materially contributed to the condition from which he
suffered.
• Case law makes it clear that in a multiple cause case the claimant simply
has to show that it materially contributed to the damage.
• Both McGhee and Bonnington can be differentiated from Wilsher because,
in the latter, the defendant’s breach of duty could not be shown to have
made a material contribution to the claimant’s harm.
4 Divisible and Non-Divisible Injuries: Dam-
ages
• In Holtby v Brigham and Cowan (Hull) Ltd [2000] 3 All ER 421, the
claimant’s injury could be divided; for the injury was asbestosis, which
was contracted whilst working for various employers and being continually
exposed to asbestos.
• As the injury was divisible, the court apportioned the damages to be paid
according to the length of time Mr Holtby had worked for each employer
and been exposed to asbestos.
• Of course, some injuries cannot be divided up in this way.
• In this kind of situation the claimant is entitled to recover their damages
in full from either one of the defendants.
• This is much better for the claimant than the situation in Holtby; the
claimant needs to bring proceedings against only one defendant in order
to recover their damages in full.
• Where two or more people are responsible for the same damage, the Civil
Liability (Contribution) Act 1978 gives the court power to apportion the
damage between them.
2
March 20, 2023
1 Factual Causation: But-For
• To establish that a breach of a duty of care caused damages, causation in
fact needs to be established.
• Like the notion of factual cause in criminal law, causation in fact is deter-
mined through the ‘but-for’ test.
• Barnett v Chelsea and Kensington Hospital Management Committee [1969]
1 QB 428 is a leading case on this; for it was shown that, but-for the de-
fendant’s breach of their duty of care to the claimant, the claimant would
still have died. Thus, the defendant’s breach of their duty of care to the
claimant was not causative of the claimant’s death.
• As tort falls under civil law, to establish causation, the claimant must
show that the harm suffered was caused by the defendant on the balance
of probabilities.
• In Hotson v East Berkshire Area Health Authority [1987] 2 All ER 909,
as the claimant could not prove on the balance of probabilities that the
defendant’s breach of their duty of care to them caused their injury, the
claim failed.
2 Factual Causation Again: But-For
• The question of causation can be much more difficult to answer when there
are several possible alternative causes of the claimant’s injury.
• For example, in Wilsher v Essex Area Health Authority [1988] AC 1074,
the evidence was that there were up to five causes of the victim’s injury.
And, as the claimant had not proven on the balance of probabilities that
the doctor’s negligence was the cause of the victim’s injury, the claim was
ordered for retrial.
1
, 3 Factual Causation: Material Contribution
• As the but-for test can fail where there are many causes of damage, such
as Wilsher, the courts can look for a different test to determine causation.
• In Bonnington Castings Ltd v Wardlaw [1956] AC 613, even though there
were two distinct causes for the damage, the claimant succeeded in estab-
lishing causation because he could show that the defendant’s breach of
duty materially contributed to the disease from which he suffered.
• McGhee v National Coal Board [1973] 1 WLR 1 is similar; even though
there were two distinct causes for the damage, the claimant succeeded
in establishing causation because they could show that the defendant’s
breach of duty materially contributed to the condition from which he
suffered.
• Case law makes it clear that in a multiple cause case the claimant simply
has to show that it materially contributed to the damage.
• Both McGhee and Bonnington can be differentiated from Wilsher because,
in the latter, the defendant’s breach of duty could not be shown to have
made a material contribution to the claimant’s harm.
4 Divisible and Non-Divisible Injuries: Dam-
ages
• In Holtby v Brigham and Cowan (Hull) Ltd [2000] 3 All ER 421, the
claimant’s injury could be divided; for the injury was asbestosis, which
was contracted whilst working for various employers and being continually
exposed to asbestos.
• As the injury was divisible, the court apportioned the damages to be paid
according to the length of time Mr Holtby had worked for each employer
and been exposed to asbestos.
• Of course, some injuries cannot be divided up in this way.
• In this kind of situation the claimant is entitled to recover their damages
in full from either one of the defendants.
• This is much better for the claimant than the situation in Holtby; the
claimant needs to bring proceedings against only one defendant in order
to recover their damages in full.
• Where two or more people are responsible for the same damage, the Civil
Liability (Contribution) Act 1978 gives the court power to apportion the
damage between them.
2
