D Carey (The Weekend Sun, July 3) asserts cannabis laws have failed yet a major NZ study has shown that use amongst younger people is declining.

Surely this proves that prohibition, coupled with associated messages around harm to physical and economic wellbeing, is actually working.

Certainly legalising and at the same time trying to educate on the harms is completely contradictory.

Experience in Canada also shows that the black market has moved to maintain its market share by dropping prices and the compliance costs and taxes legal companies will have to pay here will always make their prices higher.

What has proved to work in Portugal is a true health-based decriminalisation system - users caught with a 10 days or less supply face a range of sanctions (eg compulsory dissuasion education, fines, loss of passport etc) .

Those caught with more (suppliers, growers etc) face the full force of our current laws and criminal penalties.

This has lead to 50 per cent reduction in conviction and imprisonments. Facts not academic theory.

The real crime is that this is not the third referendum option but if we vote ‘No' then it will still be an option in future.

B. Ingram, Papamoa