The irony that Gordon Brown, Jacqui Smith and others are overlooking is that the availability of particularly strong strains of marijuana is a direct result of prohibiting users from growing a few plants for personal use only, as most users would be satisfied with reasonably potent marijuana and would not put in the time, effort and money required to produce especially strong strains.
In addition, the authorities are overlooking the health benefits of stronger strains. More potent marijuana requires less smoking to achieve the desired effect, thus reducing any possible harm to the lungs, and I need hardly point out the paucity of evidence supporting the theory that using marijuana is more harmful than spending five years in prison.
With respect to the notion that marijuana may trigger "mental health problems" in some users, that is true for many pharmaceutical drugs, but they are not prohibited for that reason. It is simply noted that the drug is contra-indicated for individuals who suffer that potential side-effect. In any case, treating marijuana users as criminals creates far more mental health problems than using marijuana ever will.
Since widespread marijuana use threatens the profits of the pharmaceutical industry, one has to ask, "Is the pharmaceutical industry lobby now controlling the British government's marijuana policy?"

George Kosinski, Gibsons, Canada