Intoxication (Involuntary)

The Law Commission's report to Parliament on Intoxication and Criminal Liability describes the situation that triggers involuntary intoxication: it arises where D commits a crime when he or she has been affected by a drug through no (or no significant) fault of his or her own, as when D's food or drink has been surreptitiously 'laced' by a third party, or D has been forced to take a drug against his or her will.

Unlike voluntary intoxication, the resulting rule applies without the specific/basic intent distinction. The report states plainly: if D did not act with the subjective fault required by the definition of the offence because of involuntary intoxication, then D cannot be convicted of the offence — and describes this as a rule with no exceptions, since no distinction is drawn between culpable states of mind labelled as 'specific intents' and other culpable states of mind the prosecution has to prove.

The defence only bites where the intoxication actually prevented the defendant forming the required mental state for the offence. If, despite being involuntarily intoxicated, the defendant still went on to form that intent, the involuntary nature of the intoxication does not by itself excuse them — the question is always whether the required fault element was actually present, not simply whether the defendant was involuntarily intoxicated at the time.