Because this action would have more effect on reducing crime than any other measure or all other measures combined.
Parliament creats crimes. People commit them
Every time a criminal offence is created by our parliament an opportinity is presented for people to break the new law and make themselves criminals.
The best way of reducing crime is to reduce the number of crimes on the statute books.
The Misuse of Drugs Act 1971 and the trafficking Acts and the three UN Convemntions not only create more opportunities for people to become criminals than all other laws and treaties put together, it hands the monopoly for the production, supply and distribution of the most profitable and largest trade in the world to these self-made criminals.
They then control this trade and encourage others, who need their products, to committ more crimes such as burglarly and muggings and murders.
About sixty percent pf the world's incarcerated criminals are people who have been caught up in this web. More people have been killed in the drugs wars in Mexico, in the last three years alone, than all the combatants in the recent and current Yugoslavian, Iraqi and Afghan wars.
All current anti-crime laws encouarge crime it and kill more people than all wars.
All these laws and treaties should be repealed and governments should take control of all systems for the supply of all drugs.
Perhaps one simple law and one simple treaty could then handle the few disprited and foolish dealers who still insist on competing with the properly controlled and leagal system.
Within 20 years all our prisons would empty, addicts could seek safe and effective treatment safe from the fear of state oppression and the crime and killing would stop.