Sir, Were cannabis to be legalised/decriminalised, the strength of
tetra-hydrocannabinol in each "cigarette" would presumably be
controlled. This is the component in the plant which has an effect on
the user.

Its strength varies according to where the plant is grown; that is,
the hotter the climate, the faster cannabis grows and the strength of
the THC is therefore greater. Also, the strength varies according to
which part of the plant is used, the most potent being the female seed.

Legalisation would allow the user to purchase cannabis through
licensed premises, rather than through the criminal underworld.
Contamination with powders, including heroin, is not uncommon, and
thus the relatively innocent user is introduced to harder drugs.
Whether cannabis is addictive is still uncertain, particularly in its
milder forms.

Yours truly, MARY BUCK, (Probation officer, 1974-2000), Pond House,
30 Ham Common, Richmond, Surrey TW10 7JG.