CHAPTER II — GENERAL PRINCIPLES OF CRIMINAL RESPONSIBILITY

PART 6 — CIRCUMSTANCES IN WHICH THERE IS NO CRIMINAL RESPONSIBILITY

Division 1 — Circumstances Involving Lack of Capacity

Mental impairment

28.— (1) A person is not criminally responsible for an offence if, at the time of carrying out the conduct constituting the offence, the person was suffering from a mental impairment that had the effect that—

(a) the person did not know the nature and quality of the conduct ; or
(b) the person did not know that the conduct was wrong (that is, the person could not reason with a moderate degree of sense and composure about whether the conduct, as perceived by reasonable people, was wrong) ; or
(c) the person was unable to control the conduct.

(2) The question whether the person was suffering from a mental impairment is one of fact.

(3) A person is presumed not to have been suffering from such a mental impairment. The presumption is only displaced if it is proved on the balance of probabilities (by the prosecution or the defence) that the person was suffering from such a mental impairment.

(4) The prosecution can only rely on this section if the court gives leave.

(5) The court must return a special verdict that a person is not guilty of an offence because of mental impairment if and only if it is satisfied that the person is not criminally responsible for the offence only because of a mental impairment.

(6) A person cannot rely on a mental impairment to deny voluntariness or the existence of a fault element but may rely on this section to deny criminal responsibility.

(7) If the court is satisfied that a person carried out conduct as a result of a delusion caused by a mental impairment, the delusion cannot otherwise be relied on as a defence.

(8) In this section—
“mental impairment” includes senility, intellectual disability, mental illness, brain damage and severe personality disorder.

(9) The reference in sub-section (8) to mental illness is a reference to an underlying pathological infirmity of the mind (whether of long or short duration and whether permanent or temporary), but does not include a condition that results from the reaction of a healthy mind to extraordinary external stimuli.

(10) A condition that results from the reaction of a healthy mind to extraordinary external stimuli may be evidence of a mental illness if it involves some abnormality and is prone to recur.