(1) A person who has actual possession of a quantity of a
prescribed restricted substance exceeding the quantity prescribed for the
purposes of this subsection is, for the purposes of any proceedings for an
offence involving the supply of a quantity of that substance, taken to have
possession of the substance for the purposes of supply unless the person--
(a)
proves the contrary, or
(b) proves that the possession of the substance was
obtained in accordance with the prescription of a medical practitioner, nurse
practitioner, midwife practitioner, optometrist, podiatrist, dentist or
veterinary practitioner.
