My Lords, because we believe that our policy is not only right but evidence-based and that we are making progress. I know that the noble Lord dissents from that view and that other noble Lords take a similar view to a greater or lesser degree. It is for that reason that have begun to set out the strategy that we have and why we have decided further to consult on the way in which that strategy should be perfected.

To make our position plain—it is worth putting this on the record—we do not accept that legalisation and regulation are now, or will be, an acceptable response to the presence of drugs. As I said earlier, my right honourable friend the Prime Minister reinforced that view at the recent Labour Party conference when he said that,

"drugs are never going to be decriminalised".

Legalisation is not open to us in view of our international obligations. I know that some noble Lords dissent from that, but that is our view. The current policy of prohibition on drugs is international and is governed by UN conventions that make unlawful the production and supply of many harmful drugs and limit possession exclusively to medical and scientific purposes. It would be wrong for us to lose sight of that perspective. There is no effective cost-benefit analysis of such a policy, if one could be made. Any such policy would need to address the international dimension.

The impact of legalisation on levels of consumption globally is key to any meaningful cost-benefit analysis. Without accurate figures for this, it is impossible to ascribe meaningful figures to the likely public and individual health cost or properly to assess the impact on productivity and industry or on the level of industrial or traffic accidents. Such fundamental difficulties call into question whether the task is an appropriate use of research funding. The impact of drugs on health is the only legitimate reason for control, and there is overwhelming evidence that the widespread use of these drugs worldwide results in enormous social harm and economic costs associated with that use. That includes the many thousands of drug-related deaths, the spread of HIV/AIDS and hepatitis B and C through injecting drugs, and the mental health disorders associated with the use of drugs.

The Government, like the international community generally, believe that the prohibition of narcotic and psychoactive drugs is a crucial element in keeping the level of drug use under control. Such drugs would become easier to access if they were to become legally available, and we would expect levels of use and the resultant harm and costs to individuals and society to expand significantly in the way in which alcohol and tobacco use has done. We do not intend to give a green light to such drug use. We do not take this robust stance lightly. We acknowledge that there are apparent benefits to an alternative system to prohibition, such as taxation, quality control and a reduction on the pressures on the criminal justice system, but in our view these are outweighed by the costs to the physical and mental health of individuals and society that result from dependence on, and addiction to, what are mind-altering drugs. Legalisation would not safeguard these very real public health interests or allay the concerns; nor would it necessarily significantly undermine international organised crime. For this reason, the Government will not pursue legalisation either domestically or internationally. It is all too easy to lay the problems of the use and misuse of drugs here and abroad simply at the door of prohibition.