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not to the exceptional rule, explained but not applied in Clements, under
which “material contribution to the risk” of injury may suffice to meet the
What then is to be made of the fact that in the final quoted paragraph
above the court says both (1) that the “but for” test “may be modified” in situations
involving multiple wrongdoers, and (2) that “a showing of ‘but for’
causation will not be necessary” where failure to disclose is caused by both
police and prosecutorial misconduct, provided the prosecutorial misconduct
“materially contributed to the harm suffered”?
Since to attract liability the prosecution must have “materially contributed
to the harm suffered”, it does not seem possible that liability is to
be imposed on the basis of contribution to “the risk” that the harm might be
suffered, but rather under the rule in Athey as explained in Clements, where
several wrongdoers actually caused the harm.
To establish liability on the part of the prosecution, it would appear that
“a showing of ‘but for’ causation” on the part of the prosecution alone “will
not be necessary”, provided that its wrongdoing made a material contribution
to causing the harm.
Henry thus appears to apply the “but for” test, as adopted in Athey and further
explained in Clements, so as to render the Crown liable only where the
prosecution is shown to have materially contributed to actually causing the
This view finds support in Conseil-scolaire francophone de la Colombie-
Britannique v. British Columbia (Education)42 and Canadian Union of Postal
Workers v. Her Majesty in Right of Canada.43
The difficulties that can be created by the concept of “but for” causation
and its terminology are particularly apparent in Henry.
SUMMARY AND A PLEA FOR CAUTION
The law of causation is plagued by confusion with respect to variable standards
of proof, overlapping terminology and extremely subtle distinctions.
For those venturing into the law of causation, it is advisable, perhaps more
than in many other areas of the law, to take a “holistic” approach to the subject
in order to be able to understand how the law has evolved and if possible
avoid pitfalls into which others have fallen.
Closely related issues beyond the scope of this paper, include (1) contributory
fault and contribution, (2) intervening act, (3) mitigation, (4) remoteness,
(5) “thin skull” and “crumbling skull” doctrines, (6) divisible and
indivisible injuries, and (7) “loss of a chance”,44 all of which should be canvassed
in association with any causation analysis.