The UK Government specifically claims the benefits of any move away from prohibition towards legal regulation of drug markets would be outweighed by the costs. No such cost-benefit analysis, or even a proper Impact Assessment of existing enforcement policy and legislation has ever been carried out here or anywhere else in the world. Yet there are clear Government guidelines that an Impact Assessment should be triggered by amongst other things, a policy going out to public consultation or when ‘unintended consequences’ are identified, both of which have happened with drug policy in recent years.
So, Transform set out to do as much of a cost-benefit analysis as they could. Using, as far as I can tell, the Governments own figures. They came up with the following numbers:
The net annual benefit of a move from prohibition to legal state regulation and control of drug markets would be:
Scenario a) 50% fall in use, net benefit = £13.943 billion
Scenario b) No change in use, net benefit = £10.834 billion
Scenario c) 50% increase in use, net benefit = £7.724 billion
Scenario d) 100% increase in use, net benefit = £4.616 billion
That is, if drugs were legalized and controlled by the Government and use of Heroin and Cocaine subsequently doubled (there's evidence that when cannabis was briefly reclassified as a Class C drug that that usage among 16-24-year-olds actually fell). The Government would be £4 billion better off, which could probably go someway to paying for AIG's next big party.
I really don't have the time or the expertise to question Transform's sums, but that looks like a good deal to me...