As a police officer for nearly 34 years, I have witnessed the worsening problems of drug addiction – whether it's to controlled substances or legal drugs, such as alcohol. The Misuse of Drugs Act 1971 has prevailed throughout my time of service, but it would appear not to have had the impact that optimistic legislators planned.

Throughout those 34 years, I have recognised that it is an indisputable truth that drugs are bad. Occasionally, a retired colleague advocates a change, but mostly politicians, professionals and the media collude in the fiction that we are winning the war on drugs, or if not, that we still have to fight it in the same way.

Their message has been successful in winning support. Indeed, I recently joined a debating society event at the University of Durham, during which I argued for the decriminalisation of Class A drugs. I felt that our team was funnier, as well as better-informed and more erudite than the opposing team, who were advocating maintaining the status quo. Imagine my surprise, my chagrin even, when the students overwhelmingly voted in favour of maintaining outright prohibition.

So, are we really winning the "war on drugs"?

Well, if the war on drugs means stopping every street corner turning into an opium den and discouraging the mass consumption of laudanum – as happened during the 19th century – then it has succeeded. But if the war on drugs means trying to reduce the illicit supply of drugs, then it has comprehensively failed.

One of my custody sergeants, who was discussing addiction at an event recently with Recovery Academy Durham, noticed the absence of a former addict we worked with called Gary, who is in his 40s and has been on drugs ever since he was 14. Gary had not been arrested recently, so it was concluded (wrongly) that "well, he must be dead". That is the shocking truth – the Garys of this world are either in prison, regularly arrested or dead. But can we not come up with a better way of helping people like him?

Not all crime gangs raise income through selling drugs, but in my experience most of them do. So offering an alternative route of supply to users cuts off the gang's income stream. If an addict were able to access drugs via the NHS or some similar organisation, then they would not have to go out and buy illegal drugs. And buying or being treated with diamorphine, say, is cheap.

Drugs should be controlled. They should not, of course, be freely available. I think addiction to anything – be it drugs, alcohol gambling or anything else – is not a good thing, but outright prohibition just hands revenue streams to villains. Since 1971, prohibition has put billions into the hands of villains who sell adulterated drugs on the streets.

If you started to give a heroin addict the drug therapeutically, we would not have the scourge of hepatitis C and HIV spreading among needle users, for instance. I am calling for a controlled environment, not a free for all. In addition, I am saying that people who encourage others to take drugs by selling them are criminals, and their actions should be tackled. But addicts, on the other hand, need to be treated, cared for and encouraged to break the cycle of addiction. They do not need to be criminalised.

The approach to banned substances contrasts sharply with our attitude towards alcohol. I am deeply disappointed that the government has not followed through on its initial support for a minimum price for alcohol. In the north-east we suffer immense inequalities in health and life expectancy due to alcohol addiction. Is it fair that alcohol-related crime and licensing costs society in my own force area alone at least £65.8m a year?

Is it sensible that in County Durham, you can buy two litres of strong cider for just £1.99? I suspect it has never seen an apple, but is more akin to industrial ethanol. Social tolerance of excessive drinking has become far too great.

While having a drink was once only one part of socialising, many people now believe that the only purpose in going out of an evening is "to get smashed". The only consequence of their night out is a horrific hangover and vomit-stained clothing.

Drug addiction costs us a fortune, but it pales in comparison to the depredations of alcohol problems. All of this fuels the increasingly distressing problem of mental ill-health. Whatever the causes, the police are now mostly the first port of call and often the only agency called on and are then expected to deal with the impact of mental ill-health on society.

Have we not learned the lessons of prohibition in history? The Mob's sinister rise to prominence in the US was pretty much funded through its supply of a prohibited drug – alcohol. That's arguably what we are doing in the UK.

Britain's police forces all map the activities of organised crime. In my force area we have 43 organised crime groups on our radar. Most of them have their primary source of income in illicit drug supply; all of them are involved in some way.

These criminals are often local heroes and role models for young people who covet their wealth. Decriminalising their commodity will immediately cut off their income stream and destroy their power. Making drugs legal would tackle the supply chain much more effectively and much more economically than we can currently manage.

My argument for decriminalising drugs may seem paper-thin when one considers that alcohol is legal and yet extremely damaging. What I am saying is that we need to have a more honest debate.

But I leave you with the optimistic words of our friend, Gary, who is now methadone- and drug-free: "The future is rosy."