The presumption of innocence places the burden of proof on the prosecution. It must prove every essential element of an offence beyond a reasonable doubt; the accused need prove nothing.
Section 11(d) of the Charter constitutionalises the presumption. A statute that reverses the onus — requiring an accused to disprove an element — infringes section 11(d) and will stand only if it can be justified as a reasonable limit under section 1.
The House of Lords held that the prosecution must prove the guilt of the accused — the “golden thread” running through the criminal law. Subject to narrow exceptions, no burden rests on an accused to prove innocence.
The Court set out the test for when a limit on a Charter right can be justified under section 1: the objective must be pressing and substantial, and the means proportionate — rationally connected to the objective, minimally impairing of the right, and proportionate in their overall effect.