It's a policy that would be a hammer blow to criminal gangs. It would stop criminalising non-violent people, drastically undermine racist policing, be good for people's health and it would save lives. But while a mainstream British politician is more likely to have smoked cannabis than to propose its legalisation, the courageous Uruguayan government has done just that.

Uruguay made a pragmatic choice. It could continue to leave cannabis production and sale in the hands of violent criminal gangs, or the state could take it over and regulate it properly. “A regulated market that is visible has greater oversight than prohibition,” as Diego Canepa, the president of the Uruguay's National Drug Board, has put it. Uruguayans who register on a national database can buy up to 40g of pot from a pharmacy, and adults are now allowed to grow up to eight marijuana plants each.

The gangs of Uruguay must be incandescent with rage. The so-called “war on drugs” has been the ultimate money-spinner for the criminal underworld. In the five decades since its catastrophic inception, more people are using drugs than ever before, and the illegal market is booming. According to the UN, it is now worth $330bn globally a year, which is bigger than most countries' economies. Governments spend $100bn a year supposedly cracking down on it. The US alone has thrown a trillion dollars at it since Richard Nixon unleashed his war. It is a self-destructive waste on an epic scale.

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Just look at the fruits of Britain's war on drugs. In 1970, 9,000 people were cautioned or convicted for drug use. Quarter of a century later, the figure had leapt to 94,000, and last year it reached 133,000. According to the Crime Survey for England and Wales – with all the caveats of the problems of self-reporting – 36.5 per cent of British adults have tried drugs. What exactly is being served by treating so many millions of Britons using a drug far less dangerous than alcohol as though they are criminals?

As demand for drugs has grown, attacks on its supply have simply driven up the cost. That's not something that only gangs can capitalise on - it helps drive other forms of crime, too. It’s been estimated that around half of property crime in Britain is drugs-related because users steal to fuel their expensive habit.

It has destabilised entire nations, leading to thousands of deaths. Around 60,000 people have died in drugs-related violence in Mexico since 2006, and the violence escalated as then president Felipe Calderon unleashed the might of the state against the cartels. No wonder Uruguay's President José Mujica has declared that “the effects of drug trafficking are worse than those of the drugs themselves”.

People are criminalised for non-violent offences, in some cases ruining lives. It has a frightening racist dimension, too. In the United States, for example, two-thirds of those languishing in prisons for a drug offence are black or Hispanic, even though the odds of them either selling or using drugs is roughly the same as white Americans.

It is a similarly bleak story in this country, too. As pioneering drugs charity Release has found, black people are more than six times likely to be stopped and searched on suspicion of drug possession in London, even though they are actually less likely to use drugs. Disgracefully, a black person found with cannabis on them is five times more likely to be charged than a white person. This is outright racism. But we should simply stop persecuting people for having weed in their pockets. Six out of 10 people being prosecuted for drugs possessions are being done for cannabis. For what? Legalising cannabis would drastically decrease the involvement that ethnic minority people have with an institutionally racist justice system.

When it comes to problematic drug abuse and addiction, a more constructive approach would be to deal with the causes, not the symptoms. All the studies show that problematic drug use is far more common in poorer communities. Let's deal with poverty and leave prisons to the violent, the rapists and the killers.

With cannabis in the hands of the state, we can get rid of bad-quality and more dangerous forms of the drug. We can impose age restrictions. We can separate the market. At the moment, drug gangs can encourage cannabis-users to take other more dangerous drugs. By taking it out of the black market, we can get the lost tax revenues. We can free up time and resources battling cannabis and put it to far better use.

We've had 50 years of the war on drugs, and the results are in: it is an absolutely calamitous failure. Albert Einstein famously defined insanity as “doing the same thing over and over again and expecting different results”, which may as well be the slogan of the proponents of this criminal escapade. They are the best friends of the profiteering criminal gangs, who they would leave in monopoly control of drugs. When will British politicians show the farsightedness and courage of Uruguay? Because until they do, money will continue to be wasted, lives will be ruined, and people will keep dying. It is quite a price for stubborn stupidity.