Cannabis use is something that will always go on, whatever the law says.
Although it can provoke psychosis in a few, it is also beneficial for a number of medical conditions. It shoudl be the individual's right to decide whether they wish to use it or not, in the same way that we choose alcohol, smoking, coffee, hot dogs and other things which may not be good for our health.
People who choose to smoke cannabis are currently forced to go to criminals to buy it, where they may come into contact with harder, more dangerous drugs.
Forcing them to buy off the street means that they are often buying cut or contaminated cannabis which can do them harm.
Buying on the street supports criminal activity and the smuggling in of cannabis to the country.
If people could grow their own they would be able to keep apart from petty criminals and gang rackets, the courts woudl be freer, it woudl undermine the mass producers and make the bottom fall out of the market so ther eis no financial incentive ti smuggle in cannabis or set up "factories" in this country.
Those with medical conditions that are helped by cannabis will be more self sufficient and not be costing the NHS so much money.
It will free up police time.
It wil not make criminals out of ordinary people who are just seeking some relief from a long term medical condition.