That is a sensible and coherent response to the problem. However, the difficulty is that, once prison has become part of a drug user's life, it is difficult to break the cycle. Prison is often one of the most difficult places in which to keep people away from drugs, and there is often a reluctance to use punitive measures as a response to dealing and drug taking. I remain convinced that such measures are not the only proper solution for those who deal in and take drugs.
I am not sure that we need a commission on cannabis, because I am convinced that it has long-term psychological effects on people who use it in vast quantities. There is even some evidence that weekly use can cause difficulties. The hon. Gentleman's Bill refers to those who are affected by other people's use of cannabis. That can be especially relevant in regard to driving and to people in the workplace. However, I am wholeheartedly against a strict measure for testing for drugs in the workplace. I firmly believe that a much better approach exists. My local drug and alcohol team have developed a fantastic toolkit to encourage employers not to go straight in with mandatory drug testing but to find ways of supporting their staff and of giving them access to treatment for their drug use. Using the workplace as a forum in that way makes it more of a place of safety for everyone, and helps people to understand that it is dangerous to take drugs in the workplace as it might endanger their colleagues. It also gets across the message that it is important to get them off the drugs, rather than driving them into taking more serious drugs. We have found that that can happen in prison, because cannabis can be detected in a urine sample for up to 30 days, while many class A drugs—particularly opiates—have gone after 48 hours. This is a difficult and complex matter.
I serve on the Joint Committee on the draft Mental Health Bill, and we have paid many visits to places that treat people with mental health problems, as well as looking in detail at why people get into those situations and at the effect of drug taking on mental illness. It is a difficult issue. Does the mental illness come first, followed by self-medication with cannabis to make the person feel calmer and less anxious? Or can there be a dual diagnosis, in which a person takes cannabis and then becomes psychotic? The jury is still out on that one. It is an interesting issue to study. I am not entirely sure that a commission could get to the bottom of it, because there should be a medical response to such cases and it should be medics who look at those issues. There is plenty of evidence to show that there are problems around cannabis use, but it is difficult to determine whether the psychosis has been prompted by its use, or whether it is being used for self-medication by someone who is feeling unwell. But it is the job of the medical profession to make that determination.