Mr Clarke strongly believes that the first step towards reforming our approach to the developing drugs problem should be to decriminalise the use of cannabis. "You could save an absolute fortune in police time and money at a stroke, and that money could better spent on health awareness and education programmes," said Mr Clarke, who lives near Oldham in Lancashire.
It was his experience on city streets that led to Mr Clarke's change of attitude towards tackling the drug issue. "In the beginning, like everyone else, I was convinced that this was a law and order issue, and that we had the resources to enforce our will and the law," he said. "Towards the end of my service I saw that this was really a medicinal issue. I got tired of seeing otherwise innocent young kids from all walks of life getting criminal records for, in effect, doing nothing more than millions of other people in society were doing with alcohol."
Mr Clarke makes it clear that his personal loathing of drugs and the drug culture remains intact and, as the father of two daughters, he is well aware of parental anxiety surrounding the argument.
"The truth is that when people smoke cannabis or consume alcoholic drinks they are abusing their bodies in some way. I take the view that what I do with this carcass of mine is my own affair so long as I do not actually do anyone else any harm. If I have a drink with friends and act in a responsible way it ought not be a subject for the law to intervene in. And on that basis I do not see why thousands of people should be criminalised for taking a decision to achieve similar ends but via a different route."
Mr Clarke believes that within the police service there are many others who share his views. "I admit that I was in a minority, albeit a significant minority among senior officers, but there is a substantial groundswell of opinion among junior officers who believe that exacting criminal penalties for the simple possession of cannabis is wrong. It is, however, very difficult for serving officers to speak out on this issue, and consequently there is no debate."
The solution to the long-term question of how drugs are regulated in Western societies requires an international approach, he argues. "We have to tackle the problem in the Third World, where the bulk of the supply comes from. Over the years we have tried a variety of approaches regarding the producer nations, including a scorched earth policy. Unfortunately that only improved the quality of the crop the following year The pressure on the poor farmers in the Third World is intense. Given the personal choice of risking seeing your children die if you plant a coffee crop, or guaranteeing a good cash return for cannabis plants or opium poppies, it is easy to see how problems arise."
Mr Clarke advocates an open intervention policy whereby the developed economies agree to purchase fixed amounts, and in doing so stabilise prices and quality. "That which was surplus to requirements could be stockpiled in the way that grain and wine is. Gradually, we could subsidise Third World farmers into producing food crops once more, and both halves of the trading partnership would benefit."
The former police officer has shared his views on drug policy reform with the Minister without Portfolio, Peter Mandelson, and Labour Party research workers. "After speaking to a party official I got the impression that a Labour government in its second term would change the law. But in the meantime it would make very good sense to separate cannabis from the terms of the 1971 Misuse of Drugs Act. We need to remove the criminality."