It is difficult to write about drug legalisation without sounding like a washed-up hippie pontificating to the wall alone in a bedsit. This is possibly not unconnected to the fact that campaigners often smoke quite a lot of weed. Yet regardless of whether your preferred vice is a crack rock or a nice cup of cup of tea, there are serious, objective motivations for legalisation which are often ignored by the media in favour of shock stories about kids getting twisted on mephedrone and severing intimate parts of their anatomy.

In September last year, the Institute for Economic and Social Research published a cost benefit analysis of marijuana legalisation. This will partially be derived from inevitably heavy taxation. Since weed was legalised in Colorado at the turn of the year, the cost for an eighth has risen from $25 to around $65. In comparison, the UK street price currently sits at £20 for the same amount. Voters in Colorado approved a 15% sales tax and 10% excise duty on marijuana, and the state subsequently forecasts $70m of tax profit in 2014 alone. ISER predict annual tax revenues between £0.4 and 0.9bn in England and Wales.

But the economic benefits are not solely thanks to the highly taxable nature of any legal stimulant. Legalisation would substantially decrease the enormous financial toll drug-related crime places on society by reducing policing and criminal justice costs, and bolster the economy through other factors such as a reduction in the “scarring effect” of criminal records in the labour market. Overall, the ISER study draws together 13 separate cost benefits of unilateral marijuana legalisation to conclude that “the contribution of cannabis licensing in England and Wales to reduction of the government deficit is expected to lie in the range £0.5- £1.25bn”. This is serious money.

Yet marijuana is only one drug amongst hundreds, and total decriminalisation would correspondingly have a far more significant economic and social impact. Drug reform charity Transform tentatively suggests that the UK could save around £14bn a year if all drug use were legalised: coincidentally almost exactly the same amount that drug-related crime costs us each year. Unfortunately, lobbyists from the tobacco and alcohol industries, who for obvious economic reasons are keen to avoid other stimulants being legalised, have the ear of the government in a way that reform charities do not. Furthermore, the worldwide illegal drugs trade is worth £300bn annually- 8% of the total global economy. Governmental regulation would go some way to withdrawing the UK from this black market and breaking the stranglehold of drug cartels in Afghanistan, South America and elsewhere.

Discourse around drug use and legalisation often unhelpfully lumps all these stimulants together into one issue, when in reality the social impact of heroin is entirely different from the impact of marijuana or MDMA or any other mood-altering chemical. To say someone “does drugs” is effectively meaningless, any more than saying someone “does a job” or “does socialising” or “does crimes” tells you anything about the individual in question. It covers such a broad spectrum of activities that there is no “typical drug user”. Drug use is unique amongst criminal activities as in itself it affects no-one but the person in question. You cannot be arrested for any other activity which involves nothing but sitting quietly alone in your room.

There is therefore also an important distinction to be drawn between recreational use and problematic, addictive use provoked by poverty and despair. Drug-related crime occurs almost invariably amongst PDUs (problematic drug users). If the government is serious about getting tough on crime and tough on the causes of crime, it needs to address the social factors which lead to problematic use, not rely on prohibition.

The way in which drug crimes are currently dealt with is also in urgent need of reform. It is telling that black people are over six times more likely to be arrested for drug-related crimes than white people, despite being only half as likely to be drug users. Once arrested, they are nearly twice as likely to be charged rather than cautioned. This institutional racism is mirrored in disproportionate arrest rates in poorer communities. Stop-and-search policies deliver only a 7% arrest rate. Not only do they interfere with our right to free movement but they are an arbitrary way of administrating justice which actively encourages racism on the behalf of the police.

This insufficient, brute force approach is mirrored across the criminal justice system. At the moment, people who develop addictions as a consequence of complex social and medical factors are forced through a system which is little more than a breeding ground for addiction and repeat offences. One in six inmates develop new drug addictions in prison.

At the moment, our drug policy is actively regressing. The innocuous stimulant khat, a mild drug of cultural significance to many people of East African origin and effectively no health risk, has just been banned. With this resistance to reform in mind, the model implemented in Portugal in July 2001 presents an attractive middle-ground to total legalisation. Possession of small amounts of any drug is still illegal, but carries an administrative rather than a prison sentence. A board made up of a social worker, a psychiatrist, and an attorney deals with each case. Fines and restrictions of movement are possible, but the board is also supported by a network of substitution treatment, rehabilitation centres and re-integration services. The focus is on encouraging addicts to seek the treatment they need, rather than filling prisons with people who pose no threat to society. Drug-related deaths, drug-related crimes and HIV diagnoses have fallen significantly as a result.

We have a right to put any substance we choose into our body, and the government’s responsibility is not to police this individual decision but rather to prevent the actions of drug users having a negative impact on society. At the moment, they are failing in this duty. The day when drug use is understood as an exploration of the human mind as necessary to our society as any other cultural experience is sadly still far off, but the economic and social reasons for reform are too significant to be ignored by the government. Addiction is both a social and a literal disease, yet it is treated like any other crime.