Asuccess rate of 1%. In what area of public life would we accept that? Last year, Professor Neil McKeganey of the University of Glasgow, one of the most respected academics in Britain, established that the authorities seize just 1% of the heroin that enters Scotland in any one year. He sees no reason to think this would be any different for the nation as a whole.

Where were the headlines? Surely the press, obsessed by crime and drug-fuelled violence, would have it splashed across the front page. Not a peep. Why not?

If heroin gets in, we can only suppose cocaine and other drugs are smuggled in equally successfully. Gordon Meldrum, of the Scottish branch of the Serious Organised Crime Agency, tasked with coordinating our battle against drugs smuggling, shrugs: "1% or 10% – it is not good enough." He claims that a breakthrough in targeting top smugglers is around the corner, but when asked if there is any chance of achieving the 60-70% target the United Nations estimates would be required to change fundamentally the market in illegal drugs, he simply shakes his head.

I have been making a documentary series, Our Drugs War. They are not my first films on drugs. But even I was stunned by McKeganey's 1% figure – and the lack of response. I quoted it in interviews with senior police officers, drugs advisers and politicians; few expressed surprise, few felt that current policies were remotely adequate. Most questioned whether the Home Office was the best place to make drugs policy; surely it is an issue for health. But these public figures would only express their worries away from the camera.

I would ask why they were so concerned about opening up the debate. The response was almost comic in its predictability: "The Daily Mail." Anyone who steps out of line on policy gets shot down fast. Just ask Professor David Nutt, one of the world leaders on the effects of drugs on the brain and the now ex-chairman of the government's advisory committee on the misuse of drugs. The home secretary summarily sacked him for stepping out of line.

Drugs policies have little to do with science, health risk or harm. They have been hijacked by the emotive rhetoric of moralists.

This fear of the Daily Mail is a dishonest excuse – the truth is that there is a collective lack of will to address one of our major social problems. We bury our heads and pretend that banning drugs equals regulation. Quite the reverse; driving drugs underground leaves them unregulated and consumers unprotected. Just what is in the drugs they buy, what dose is safe, what are the side effects? And not just "old" drugs such as cocaine. There's the astonishing market in synthetic drugs which has grown up largely since the banning of ecstasy – operating in grey areas of legality and fuelling weekend parties up and down the country.

As Nutt's replacement as government advisor, Les Iversen, has found, ban one and another appears. Last year mephedrone was the craze, got banned and has been replaced by naphyrone. Ban… ban… ban… As John Arthur, head of the Edinburgh drugs charity Crew, says: "It seems to make sense to ban, but it does not work. It makes things worse. It criminalises everything."

This summer the nation's kids are out on the round of music festivals where alcohol is sold more cheaply than water and tobacco companies can be sponsors. Yet to get their fix they will either end up breaking the law, buying dodgy stuff from dealers in toilets, or they will swallow many pills before the festival to avoid security checks.

The only way to control and channel this demand is to tell the truth. If a drug really kills, tell us. If it is really dangerous, tell us. But equally, be honest when it is not. Regulate supply via prescription or chemists.

Look at the impact of tobacco education. In my lifetime we have moved away from a society where we smoked in trains, planes and pubs. We have easily accepted that we cannot smoke in any of them. We have been persuaded that tobacco really kills. Yet those who choose to go on smoking are free to do so. Because they want to.

Why should other drugs be so different? Some poor souls will end up as addicts – that is inevitable. But it should be treated as an illness, not a crime. Addictions of all types are usually a product of self-medication to avoid facing the world and we should do everything to help.

Treatment is much, much cheaper than putting people through the justice system and maybe locking them up in prison – where they will come across more drugs, of course. In this age of cuts, huge savings could be made at every stage of the drugs story.

Then there is the wider context and cost – be it in Latin America, Mexico or now Afghanistan. I went to Kabul, where the west finances both sides of the conflict. On one side, soldiers die and our tax money is spent to uphold a government riddled with drug-related corruption. On the other, the huge profits from an illegal heroin trade supply over 60% of the Taliban's finance.

Drugs money in one form or another makes up almost half of Afghanistan's GDP. These vast sums are generated solely because heroin is illegal.

On the frontline our policy has been equally confused. Some years British troops in Afghanistan are ordered to eliminate poppy production; other years eradication is deemed counterproductive because it will alienate the farmers we need on our side.

General Stanley McChrystal, before he was replaced, was for leaving most farmers in peace, while the Kabul government, presumably operating on last year's plans, sent teams down to Helmand on a determined drive to eradicate.

The counter-narcotics minister in Kabul shrewdly observes that if we ever stop it here, heroin will simply be grown somewhere else – the profits are too attractive.

Regulating drugs sensibly is not a magic solution. I make no bones about the dangers of drugs, be they heroin or the industrial cleaner, GBL [gamma butyrolactone]. People will continue to die each year.

I do not wish to undervalue the real emotion of each family, but we have to start being brave enough to acknowledge the level of failure of present strategies. Drugs are not a problem of morality and crime but of health.

One per cent. As a New York congressman said to me: "The definition of insanity is to do the same thing over and over again and get the same results. It's true for the addict, it's true for the addicted society, it's true for our using a criminal justice model to solve a medical problem."

Angus Macqueen is a film-maker. His three-part Our Drugs War starts tomorrow at 8pm on Channel 4