Why can't you buy heroin at Boots? Or Watson's?

I've long thought that all so-called 'hard' drugs should be decriminalised. As it stands, the business is run by the most aggressive and often brutal specimens of humanity that capitalism can throw up. Whole countries are corrupted and wrecked by narco-, warlord- and gangsta business practices and power politics, and turned into war zones. Colombia, anyone? Afghanistan? Innercity zones in Western developed countries? Politicians, bureaucrats, customs, and police officers are bribed and corrupted along the trafficking routes. Consumers are, ipso facto, criminals. Prisons around the world are filled to overflowing with people who could otherwise be doing something else -- even something useful. If 'hard drugs' were legalised wouldn't that mean that everyone would become a drug addict? No, of course not. Alcohol is, outside of Muslim countries, freely available and not everyone turns into a raging alcoholic.
If you are interested, there is a longer and better argued piece in today's Guardian.