R v Tutton

(1989) — Exam/Oral Summary (Mens Rea Focus)

1) What happened (core facts)

  • Parents of 5-year-old Christopher, who was a known diabetic needing insulin.

  • Parents stopped giving insulin because of religious belief (faith healing) that he was cured.

  • Child became seriously ill and later died from diabetic complications.

  • Crown theory: they failed to provide necessaries of life (insulin + timely medical help).

2) Charges (what the Crown needed to prove)

  • Manslaughter by criminal negligence (based on omission under a legal duty).

  • Legal duty: parents must provide necessaries of life to a child.

  • Criminal negligence definition: omission showing “wanton or reckless disregard” for life/safety.

3) Defence (mens rea angle)

  • Defence was mistake of fact / honest belief:

    • They honestly believed the child was healed and not in danger.

    • They claimed they didn’t appreciate the seriousness of the child’s condition once insulin stopped.

4) Main legal issue (what the SCC is really fighting about)

  • For criminal negligence, is mens rea:

    • Purely objective (reasonable person standard only), OR

    • Does it require some guilty awareness (subjective advertence/wilful blindness to risk)?

5) Result (what the SCC actually did)

  • New trial ordered (appeal dismissed).

  • Reason: the jury charge was defective, especially because it didn’t clearly explain that the Crown must prove all elements of manslaughter by criminal negligence.

(So regardless of theory, they ordered a new trial due to the trial judge’s instructions.)

6) Mens rea split (THIS is what your prof will test)

A) McIntyre J (objective approach — majority on this point)

  • Criminal negligence is assessed by an objective standard:

    • Did the conduct show a marked and significant/substantial departure from what a reasonably prudent person would do?

  • Focus is on dangerous conduct, not the accused’s actual state of mind.

  • For mistake of fact in negligence offences:

    • A mistaken belief helps only if it’s reasonable.

    • An unreasonable honest belief = still negligent → not a defence.

Exam line: For negligence-based offences, mens rea is essentially objective fault (marked departure), and mistake of fact must be reasonable to matter.

B) Wilson J (would require guilty awareness — not majority)

  • Wilson J argued criminal negligence should not become absolute/objective liability with no guilty knowledge.

  • She emphasized the language “wanton or reckless disregard” suggests some awareness (advertence) or wilful blindness to the risk.

  • She worried a purely objective test could punish the morally innocent for serious crimes.

Exam line: Wilson J reads “wanton/reckless” as implying subjective blameworthiness (awareness or wilful blindness), not just unreasonable conduct.

7) Mistake of fact + mens rea (how to explain it fast)

  • In true mens rea offences, an honest mistake can negate mens rea even if unreasonable (classic idea).

  • But under the objective negligence model, the mistake must be reasonable, because the offence is about unreasonable risk-taking.

8) Why it matters (one sentence)

  • Tutton is a leading case on how mens rea works in criminal negligence, especially where the act is an omission under a legal duty and the accused raises honest belief/mistake of fact.