Guilty Knowledge/Useable Quantity

Question 1

Guilty knowledge

Answer 1

For a person to be guilty of an offence relating to controlled drugs they must have guilty knowledge; a person who innocently possesses something they genuinely believed was not a controlled drug has a defence.

However, although the defendant must know that the substance was a controlled drug (or at least that it had characteristics consistent with those of a controlled drug), it is not necessary for the Crown to prove such knowledge; guilty knowledge will be presumed in the absence of evidence to the contrary. It is therefore up to the defendant to raise reasonable doubt as to their state of mind.

Question 2

R v Strawbridge

Answer 2

It is not necessary for the Crown to establish knowledge on the part of the accused. In the absence of evidence to the contrary knowledge on her part will be presumed, but if there is some evidence that the accused honestly believed on reasonable grounds that her act was innocent, then she is entitled to be acquitted unless the jury is satisfied beyond reasonable doubt that this was not so.

In R v Strawbridge4 the defendant was convicted of cultivating a prohibited plant, claiming on appeal that she had not known the plants she had cultivated were cannabis. The Court of Appeal ordered a re-trial, holding that the offence is not absolute and that mens rea is an essential element.

Question 3

Mistake as to nature of controlled drug

Answer 3

While guilty knowledge is an essential element, section 29 provides that it is not a defence that the defendant did not know the substance in question was the particular controlled drug alleged.

For example, it would not be a defence to a charge of supplying heroin if the defendant believed the drug he had supplied was in fact cocaine.

Question 4

Useable quantity

Answer 4

In any drug offence the quantity of drug involved must be measurable and useable.

Question 5

Police v Emirali

Answer 5

“…the serious offence of … possessing a narcotic does not extend to some minute and useless residue of the substance”.

In Police v Emirali5 the defendant was charged following a search warrant at his address in which minute quantities of cannabis were found. The Court of Appeal held that the purpose of the statute is not to prohibit the existence of controlled drugs per se, but to prevent their illicit use, and it was therefore necessary for the drugs found to be of a useable quantity.

Question 6

Proving useable quantity

Answer 6

While it is necessary that the amount of the controlled drug is of a useable quantity, under section 29A it is not necessary for the prosecution to prove that fact unless the defendant puts the matter in issue.